Merriam Webster

Bilious

has several meanings, including "angry or bad-tempered" and "sickeningly unpleasant to look at." Its earliest use describes things that are "of or relating to bile."

Encapsulate

means “to show or express the main idea or quality of (something) in a brief way.”

Serendipity

is luck that takes the form of finding valuable or pleasant things that are not looked for.

Gauche

means “having or showing a lack of awareness about the proper way to behave.” When describing a person or a behavior, gauche can mean “socially awkward” or “tactless”; when describing an object (such as a product with a vulgar image or slogan on it) it can mean “crudely made or done.”

Abandon (n.)

means “a feeling or attitude of wild or complete freedom,” and is often used synonymously with enthusiasm and exuberance. It also appears in the phrase with reckless abandon to describe something done without fear or concern for consequences.

Catercorner

is used as both an adverb and adjective to describe things that are situated in a diagonal or oblique position. The word is a less common variant of kitty-corner.

rapscallion

refers to someone who causes trouble, often in a mischievous way. It is a synonym of rascal and ne’er-do-well

Fustigate

means “to criticize severely.” Its older, less common meaning is “to beat with or as if with a short heavy club.”

Sallow

means "of a grayish greenish yellow color," and often suggests sickliness.

Lycanthropy

refers to the power or ability to take the shape and characteristics of a wolf through witchcraft or magic. It can also mean “a delusion that one has become a wolf.”

Scour

means “to search (something) carefully and thoroughly.” Scouring is usually associated with moving quickly.

Notorious

describes people and things that are famously known, especially for something unfavorable.

Sepulchre

is an old-fashioned word for a tomb or other place of burial

Genteel

means “elegant or graceful in manner, appearance, or shape.” It can also mean “marked by false delicacy, prudery, or affectation,” or be used as a somewhat old-fashioned synonym of aristocratic.

Volition

a formal word that means “the power of choosing or determining.” Usually, though not always, volition follows own, as in “left the company of her own volition.”

Cloying

means "excessively sweet or sentimental.”

Interlocutor

a formal word that means “one who takes part in dialogue or conversation.”

Writhe

means “to twist.” The word is often used when the body or a bodily part is twisting, and especially when it is twisting in pain.

Bespoke

is a synonym of custom-made and is used to describe anything made to an individual’s desired specifications.

Frenetic

means “marked by excitement, disorder, or anxiety-driven activity.” It is synonymous with frenzied and frantic, both of which are also related etymologically to frenetic.

Cadence

is used to refer to various rhythmic or repeated motions, activities, or patterns of sound, or to a falling inflection of the voice

Transmogrify

means “to change something significantly and often with humorous or jarring effect.”

jarring

having a harshly concussive, disagreeable, or discordant effect

propriety

1
: the quality or state of being proper or suitable : APPROPRIATENESS
2
a
: conformity to what is socially acceptable in conduct or speech
b
proprieties plural : the customs and manners of polite society
c
: fear of offending against conventional rules of behavior especially between the sexes

Rabble

is used to refer to a large group of loud people who could become violent (that is, a mob), or, usually in the phrase the rabble, to refer to the great mass of regular people as contrasted with the elite. In the latter use, the word is typically applied in a humorous or exaggerated way to suggest the attitudes of the powerful and wealthy.

bombinate

make a sustained, murmuring sound similar to a buzz or drone

Avuncular

is used to describe someone or something as being "like an uncle," especially "kind or friendly like an uncle."

spiel

a fast speech—often one that has been rehearsed or given before—that is usually intended to get someone to buy something or to agree to something

Proffer

is a formal word meaning “to present (something) for acceptance.”

Gargantuan

means "very large in size or amount."

Onus

is a formal word that means “a responsibility, obligation, or burden.” It can also be used in some contexts as a synonym for blame or stigma. It is usually preceded by the word the.

emblazon

decorate its surface, usually with a name, slogan, or picture

chasm

1: a deep cleft in the surface of a planet (such as the earth) : GORGE
2: a marked division, separation, or difference

Proselytize

is a formal word that means “to try to persuade people to join a religion, cause, or group.”

Kerfuffle

is an informal word that means “a disturbance or fuss typically caused by a dispute or conflict.”

Fructify

means “to make fruitful or productive” or “to bear fruit or profit.”

caucus

“a meeting of members of a political party for the purpose of choosing candidates for an election.” It also refers to “a group of people who meet to discuss a particular issue or to work together for a shared, usually political goal.”

Anthropomorphic

means “described or thought of as being like human beings in appearance, behavior, etc.”

Misnomer

means “an incorrect name or designation.” It can also be used to refer to the act of wrongly naming or designating, as in “calling complicated and varied climatic changes ‘global warming’ is something of a misnomer.”

defer

means “to choose to do (something) at a later time.”

Perspicacious

a formal word that means “possessing acute mental vision or discernment.” Someone who is perspicacious has a keen ability to notice and understand things that are difficult or not obvious.

Verdigris

is a green or bluish deposit, usually of copper carbonates, that forms on copper, brass, or bronze surfaces

laconic

Someone described as laconic uses few words in speech or writing. The word often also implies brevity to the point of seeming rude, indifferent, or mysterious.

loquacious

1
: full of excessive talk : WORDY
2
: given to fluent or excessive talk : GARRULOUS

Coalesce

means “to come together to form one group or mass” or “to join forces.”

Rancid

means “having an unpleasant smell or taste,” and is often used to describe food that is no longer fresh. It is also used to describe something (such as an encounter) that is offensive or distasteful.

broadside

most often refers to a very strong and harsh spoken or written attack, but it has other meanings as well, among them “an attack by a ship in which all the guns on one side of the ship are fired together.”

Titivate

means "to make (someone or something) neater or more attractive," and is a synonym of spruce up.

Invective

means "insulting or abusive language." It can also refer to an abusive expression or speech.

facsimile

is an exact copy of something. The word is also used to refer to a system of transmitting and reproducing graphic matter, such as printed text or photos.

Mawkish

means “exaggeratedly or childishly emotional,” and is often used to describe works of art, music, or literature that a critic finds cloying.

Conciliate

is a formal word applied in situations in which anger or disagreement presents a need for resolution. It can mean "to make compatible; to reconcile," "to appease or win over," or "to become or try to become friendly or agreeable."

panache

Today, when we say that someone has panache, we are saying that they have energy, spirit, and style. Originally, the word referred to an ornamental tuft or plume of feathers, and especially one affixed to a helmet.

Assiduous

is a formal word that means “showing great care, attention, and effort.”

Grandiose

is most often used disapprovingly to describe something that seems impressive or is intended to be impressive, but is either not possible or practical.

Umbrage

is a formal word that usually refers to a feeling of being offended by what someone has said or done. It is often used in the phrase "take umbrage."

brandish

is to shake or wave something, such as a weapon, in a menacing manner. In figurative use, it is to exhibit something, such as one's intellect, ostentatiously or aggressively.

ostentatious

attracting or seeking to attract attention, admiration, or envy often by gaudiness or obviousness : overly elaborate or conspicuous : characterized by, fond of, or evincing ostentation

Effulgence

means "radiant splendor" or "brilliance."

Jaunty

means "lively in manner or appearance."

Devolve

means "to gradually go from an advanced state to a less advanced state," or "to pass something, such as responsibility or power, from one person or group to another person or group at a lower level of authority."

Vociferous

describes people who express their feelings or opinions loudly and forcefully, as well as things, such as objections, that are expressed in such a way.

Abrogate

is a formal word that means "to fail to do what is required by something, such as a responsibility," or "to end or cancel something in a formal and official way."

antiquated

1
: outmoded or discredited by reason of age : old and no longer useful, popular, or accepted
antiquated ideas
antiquated methods of farming
antiquated machinery
antiquated slang
2
: OBSOLETE
an antiquated calendar
3
: advanced in age

Epitome

means “a typical or ideal example,” and is a synonym of embodiment.

Unabashed

is a synonym of both undisguised and unapologetic. It usually describes someone who is not embarrassed or ashamed about openly expressing strong feelings or opinions, or such a person's emotion or behavior.

Charisma

means "a special magnetic charm or appeal." A person with charisma is captivating and often admired.

Immutable

means "not capable of or susceptible to change."

Litany

refers to a usually lengthy recitation or enumeration of something, such as a set of complaints, names, or questions. It can also be used to refer to a sizeable series or set, which may or may not be spoken aloud, as when a drug has "a litany of possible side effects."

Dilatory

means "tending or intended to cause delay." It can also mean "tending to procrastinate or be late."

Carceral

means "of, relating to, or suggesting a jail or prison."

Melancholia

refers to a feeling of sadness or depression. It is also used to refer to a sad tone or quality that one perceives in something, such as a work of art or literature.

riposte

is a clever retort or retaliatory measure. In fencing, it refers specifically to a quick return thrust immediately following a successful defensive action.

Crepuscular

means "of, relating to, or resembling twilight." It is also used in zoological contexts to describe creatures that are active during twilight, or to the activities of such creatures.

Eminently

is used as a synonym of very and means “to a high degree.”

adjudicate

To adjudicate a dispute between parties is to make an official decision about which party is right. Adjudicate is also used to mean "to act as judge."

Heartstring

used, usually in the plural, to refer to someone's deepest emotions or affections.

Brackish

is typically used to mean “somewhat salty,” and most often describes water or bodies of water, such as rivers, lakes, and estuaries.

patina

s a usually green film that forms on copper and bronze that is exposed to moist air for an extended time. The word can also refer to a shiny or dark surface that over time forms naturally on something (such as wood or leather), or to a literal or figurative thin layer.

Nebulous

is often used as a synonym of indistinct or vague, but can also be used to refer to something that is related to or that resembles a nebula.

Frolic

means “to play and run about happily.”

Menagerie

is used to refer to a collection of animals kept especially to be shown to the public, as well as a place where such animals are kept. It can also refer more broadly to any varied mixture.

aviary

a place for keeping birds confined

Ineffable

is used to describe something that is indescribable or unspeakable and that cannot be expressed in words. It is also used for things which are taboo and are not to be uttered.

Brouhaha

is a synonym of both uproar and hubbub, and can mean "a noisy confusion of sound" or "state of commotion."

Apropos

means "with regard to." It is frequently used in the phrase "apropos of."

Luddite

refers to someone who is opposed to change, and especially to technological change.

extradite

To extradite someone who has been accused of a crime is to send that person to the state or country that has jurisdiction to try them for that crime.

Pathos

refers to some element of an experience or of an artistic representation that evokes compassion or pity. The word also refers to a feeling of sympathetic pity.

muse

To muse about something is to think about it carefully and thoroughly. The word can also mean "to become absorbed in thought," or "to think or say something in a thoughtful way."

Iconoclast

originally referred to someone who destroys religious images or who opposes their veneration. It is now used to refer broadly to anyone who attacks widely accepted beliefs or institutions.

Waggish

means “resembling or characteristic of a wag”—a wag being a clever person who is prone to joking—and is also a synonym of humorous.

emolument

emolument

refers to money, gifts, or perquisites that someone receives due to their job or position.

perquisite

1
: a privilege, gain, or profit incidental to regular salary or wages
especially : one expected or promised
2
: GRATUITY, TIP
3
: something held or claimed as an exclusive right or possession

nuance

is a subtle distinction, variation, or quality in something, such as tone, color, meaning, etc.

Akimbo

means "having the hand on the hip and the elbow turned outward." It is also used in the broader sense of "set in a bent position."

saga

a long and complicated story or series of events. Saga first referred to ancient Icelandic narratives that tell of legendary figures and events of the heroic age of Norway and Iceland.

carp

means “to complain in an annoying way,” and often suggests that such complaining is habitual.

Gibbous

is most often used to describe a moon or planet that is seen with more than half, but not all, of the apparent disk illuminated.