10 Knowing & understanding

to be aware/conscious of (formal)

to know sth

to know of sth

you have some information, but not necessarily a lot

to be in the know (informal) (knowing)

you know sth special or a secret

to be familiar/acquainted with sth/to be no stranger to sth

that sth or sb is not new to you, that you know it/them already

to be at home in sth

that sb knows enough about a particular topic to want to have discussions about it

to know one's way around

that you won't get lost in a place because you know it well enough

to know a thing or two (informal)

that, thanks to your practical experience, you know a lot about a particular thing

to know one's stuff (informal)

that you know all you should know about your subject and are ready to sit for your exams, do a difficult job…

to know inside out/to know backwards/to know like the back of one's hand

that you know sth so well that you don't have to even think about it

to know better

that you know more than others

omniscient (informal)

to describe sb sho knows literally everything

well-informed

to describe sb who has good information on a particular subject or good general knowledge

learned/read

to describe sb who gets a lot of knowledge from books

proficient (proficiency)/skilled in/at sth (skilful/skill)

when talking of people who have a thorough knowledge in a particular field

expert/practised (expertise/know-how, informal)

when talking about specialized knowledge coming form experience or training

not know the first thing about sth/sb (informal)

to not know anything at all about sth

not have a clue/not have an idea (informal)

to not know a certain thing

to be in the dark/ignorant/uninformed (ignorance, U)

if you are in the dark about sth, you don't know anything about it

an inkling

if you have a vague idea about it

to make sth of sth/sb/to make sth/sb out

that you (try to) understand the meaning or character of sth or sb

to gather sth

that you understand sth by drawing conclusions

to get/to catch sth (informal)

in an informal way that you understand things you are trying to learn

to get the gist/to get or see sb's point

that you understand the main idea of sth

to get the picture/idea (informal)

that you understand a particular situation, esp one which sb's describing to you

to be with sb OR to be lost (informal)

that you (don't) understand what sb's talking about

to take sth in

that you understand what you are reading or listening to

to take a hint

that you understand sth that sb's suggesting indirectly to you

to catch on (informal)

in an informal way that you understand a suggestion, an idea, a hint or the point of sth that's said

to take sth as sth/to be

that you interpret sth in a particular way

to comprehend (comprehensible/understandable/intelligible)

in a formal way that you understand sth completely

to grasp

that you completely understand sth complicated

to digest sth

that you think about information, understand it & remember it

to realize/to dawn/to sink in

that you suddenly begin to understand the real truth or cause

to fathom

that you understand sth after you have thought about it carefully

to get to the bottom

that you find out the cause of a problem or situation

to appreciate

that you understand how serious or important a problem is

not make much of sth/sb

when you are no longer able to follow an explanation or an argument

to get sb wrong (informal)

if sb misunderstands you

to miss the point

about sb who fails to understand the main idea

to be lost OR to be with sb

asking if sb understands anything of what is being said or of what has been written

to be at sea

you don't know what to do because of lack of understanding

to be out of one's depth

you don't understand because you lack knowledge of the subject or topic

not see the wood for the trees

you don't understand because you are paying too much attention to details

not be able to make head or tail of sth (informal)

to be completely unable to understand sth; to be totally confused

to be confused/puzzled

you don't understand what's happening

to be bewildered/perplexed/nonplussed (formal) / to be baffled/stumped (informal)

you are so confused that it's impossible for you to think of a solution or to take action

to be mystified

you are mystified by things which are strange or impossible to explain or understand

insight

you gain accurate & deep understanding of complex situation or problem

wit

quick understanding

genious

U: exceptionally great mental or creative ability / C: a special ability or skill / C: a person of very great ability or very high intelligence

perceptive

quick to notice & understand things

perspicacious (formal)

clever judgement & understanding; perceptive

lucid

clear thinking / clear & easy to understand

plain/obvious OR obscure/dark

(not) clear & easy/difficult to understand

complex/complicated

difficult to understand or explain because there are many different parts

esoteric (formal)

only understood by a small number of people who have a special knowledge or interest

mystery

C: a thing of which the cause or origin is hidden or impossible to explain / C: a perosn about whom not much is known / U: the practice of making things secret

an enigma

a question, a thing, a person or an event that's very difficult to understand; a mystery