Didactic
Intended to teach, particularly in a moral sense.
Diffident
Lacking in self-confidence; shy or reserved.
Dilatory
Tending to delay or procrastinate; slow to act.
Dilemma
A difficult choice between undesirable alternatives.
Dilettante
A person with superficial interest and no commitment.
Dirge
A lament for the dead, often part of a funeral rite.
Discerning
Having good judgment; perceptive.
Discomfiture
Feeling of unease or embarrassment; confusion.
Discord
Disagreement or conflict between people.
Discursive
Digressing from subject to subject; rambling.
Disparage
To belittle or speak disrespectfully about something.
Disparate
Essentially different; diverse and not comparable.
Disparity
A great difference; a discrepancy.
Disseminate
To spread widely; distribute.
Dissolute
Lax in morals; debauched.
Distrait
Distracted or absent-minded; preoccupied.
Distraught
Deeply agitated or troubled; upset.
Diurnal
Relating to or occurring in a day; daily.
Divulge
To make known private information; reveal.
Docile
Easily managed or handled; obedient.
Doggerel
Badly written verse or words; nonsense verse.
Dogmatic
Inclined to lay down principles as true; opinionated.
Doleful
Expressing sorrow; mournful.
Dolorous
Feeling great sorrow or distress; grieving.
Drab
Lacking brightness or interest; dull.