| Term | Definition |
| deciduous | falling off, as of leaves |
| decimate | kill, usually one out of ten |
| decipher | decode |
| declivity | downward slope |
| decollete | having a low-cut neckline |
| decomposition | decay |
| decorum | propriety; orderline and good taste in manner |
| decoy | lure or bait |
| decrepitude | state of collapse caused by illness or old age |
| decry | express strong disapproval of; disparage |
| deducible | derived by reasoning |
| deface | mar; disfigure |
| defame | harm someone's reputation; malign; slander |
| default | failure to act |
| defeatist | resigned to defeat; accepting defeat as a natural outcome |
| defection | desertion (abandoning a cause) |
| defer | delay till later; exempt temporarily |
| defer | give in respectfully; submit |
| deference | courteous;regard for another's wish |
| defiance | refusal to yield; resistance |
| defile | pollute; profane |
| definitive | most reliable or complete |
| deflect | turn aside |
| defoliate | destroy leaves |
| defray | provide for the payment of |
| defrock | to strip a priest or minister of church authority |
| deft | neat; skillful |
| defunct | dead; no longer in use or existence |
| degenerate | become worse; deteriorate |
| degradation | humiliation; debasement; degeneration |
| dehydrate | remove water from; dry out |
| deify | turn into a God, idolize |
| deign | to descend to a level considered inappropriate to one's dignity:condescend; stoop |
| delete | erase; strike out |
| deleterious | harmful |
| deliberate | consider; ponder |
| delineate | portray; depict; sketch |
| delirium | mental disorder marked by confusion |
| delta | flat plain of mud or sand between branches of a river |
| delude | deceive |
| deluge | flood; rush |
| delusion | false belief; hallucination |
| delusive | deceptive; raising vain hopes |
| delve | dig; investigate |
| demagogue | person who appeals to people's prejudice; false leader |
| demean | degrade; humiliate |
| demeanor | behavior; bearing |
| demented | insane |
| demise | death |
| demographic | related to the population balance |
| demolition | destruction |
| demoniac | Of, resembling, or suggestive of a devil; fiendish |
| demotic | pertaining to the people |
| demur | objection (n) |
| demur | object ( because of doubts, scruples); hesitate |
| demure | grave; serious; coy |
| denigrate | blacken |
| denizen | inhabitant or resident; regular visitor |
| denotation | meaning; distinguishing by name |
| denouement | outcome; final development |
| denounce | condemn; criticize |
| depict | portray |
| deplete | reduce; exhaust |
| deplore | regret |
| deploy | spread out (troops) in a xtended though shallow battle line |
| depose | dethrone; remove from office |
| deposition | testimony under oath |
| depravity | extreme corruptions; wickedness |
| deprecate | express disapproval of; protest against; belittle |
| depredation | plundering |
| derange | make insane; disarrange |
| derelict | abandoned; negligent |
| derivative | unoriginal; obtained from another source |
| dermatologist | one who studies the skin and its diseases |