| Term | Definition |
| n deciduous | falling off at a specific season or stage of growth as of leaves; Ex. deciduous tree/teeth |
| decimate | kill (usually one out of ten or every tenth man); destroy or kill a large part of |
| decipher | decode; CF. indecipherable |
| n declivity | downward slope |
| n d\'ecollet\'e | (of a dress) having a low-cut neckline; CF. d\'ecolletage: low neckline (on a dress) |
| s decree | authoritative order; edict; judgment of a court of law; V: order or judge by decree |
| n decomposition | decay; V. decompose: decay; break and separate into simple parts |
| decorum | propriety; orderliness and good taste in manners; appropriateness of behavior or conduct |
| s decorous | proper (in behavior, conduct, or appearance) |
| decoy | lure or bait; V. |
| decrepitude | state of collapse or weakness caused by illness or old age |
| s decrepit | weak and in bad condition from old age or hard use; Ex. decrepit old chair/man |
| n decry | express strong disapproval of; condemn openly (something dangerous to the public); disparage; Ex. decry the violence of modern films |
| deducible | derived by reasoning; V. deduce: infer; derive by reasoning |
| deface | mar; disfigure |
| s mar | spoil the appearance of |
| defame | harm someone's reputation; malign; speak evil of; slander; N. defamation; ADJ. defamatory |
| default | failure to act; failure to perform a task or be present; V. |
| n defeatist | resigned to defeat or failure; accepting defeat or failure as a natural outcome; N. CF. defeatism |
| defection | desertion |
| s defect | shortcoming; V: desert (in order to join the opposite one) |
| defer | give in respectfully; submit; delay till later; exempt temporarily; N. deferment; CF. show respect, comply with, courteous |
| deference | courteous regard for another's wish; courteous yielding to another's wish or opinion (showing respect); ADJ. deferential; OP. effrontery |
| defiance | refusal to yield; resistance; V. defy; ADJ. defiant |
| defile | pollute; make filthy or dirty; corrupt morally; profane; desecrate; N: narrow passage or gorge through mountains |
| definitive | most reliable; authorative and complete; that cannot be improved; conclusive; decisive; definite; Ex. definitive decision by the supreme court |
| deflect | turn aside; turn away from a straight course |
| n defoliate | destroy leaves; deprive of leaves (by the use of chemicals); N. defoliant |
| n defray | provide for the payment of; undertake the payment of; pay |
| n defrock | strip a priest or minister of church authority; unfrock |
| s frock | long loose garment (worn by monks) |
| deft | neat; skillful |
| defunct | dead; no longer in use or existence |
| degenerate | become worse in quality; deteriorate; ADJ: having become worse; Ex. a degenerate species; N: depraved or corrupt person |
| degradation | humiliation; debasement; degeneration; V. degrade: debase; disgrace; degenerate; reduce (something) in worth; demote (someone); reduce in rank |
| s dishonor | disgrace; N. ADJ. dishonorable |
| n dehydrate | remove water from; dry out |
| deify | turn into a god; make a god of; idolize; Ex. Kings were deified; CF. deity |
| n deign | condescend; stoop |
| s stoop | bend forward and down; lower or debase oneself; fall to a lower standard of behavior by doing something; condescend; Ex. stoop to lying |
| delete | erase; strike out |
| n deleterious | harmful |
| deliberate | consider; ponder; ADJ: done on purpose; slow |
| delineate | portray; depict; sketch; describe; N. delineation |
| delirium | mental disorder marked by confusion; uncontrolled excitement; ADJ. delirious |
| delta | flat plain of mud or sand between branches of a river |
| delude | deceive |
| deluge | flood; rush; V. |
| delusion | false belief; hallucination; deluding; Ex. delusions of grandeur; Ex. under the delusion that |
| delusive | deceptive; likely to delude; misleading; raising vain hopes; Ex. delusive promises |
| n delve | dig; search deeply; investigate |
| demagogue | person who appeals to people's prejudice; false leader of people; CF. demagoguery |
| demean | disgrace; humiliate; debase in dignity; behave |
| demeanor | behavior; bearing |
| demented | insane |
| demise | death |
| n demographic | related to population balance; N. demography: statistical study of human population |
| demolition | destruction; V. demolish |
| n demoniac(demoniacal) | fiendish; cruel; N. demon: evil supernatural being; devil |
| s fiend | evil spirit; devil |
| n demotic | of or pertaining to the people |
| n demur | object (because of doubts, scruples); raise an objection (showing qualms); hesitate; Ex. demur at the idea of working on Sunday |
| n demure | (of a woman or child) grave; quiet and serious; coy; pretending to be demure |
| denigrate | blacken; defame |
| denizen | (animal, person, or plant) inhabitant or resident of a particular place; regular visitor |
| denotation | meaning; distinguishing by name; V. denote: indicate; refer to directly; mean; CF. connotation |
| n d\'enouement | final outcome; final development of the plot of a play or other literary work; the end of a story when everything is explained |
| denounce | condemn; criticize; N. denunciation |
| depict | portray |
| s expos\'e | public revelation of something discreditable |
| deplete | reduce; exhaust |
| deplore | regret; express sorrow and severe disapproval for something bad; Ex. deplore their violent behavior; ADJ. deplorable: very bad; deserving severe disapproval; Ex. deplorable living condition |
| deploy | spread out (troops) in an extended though shallow battle line; distribute (persons or forces) systematically or strategically |
| s battalion | army unit made up of four or more companies |
| depose | dethrone; remove from office; give a deposition; testify |
| deposition | testimony under oath; deposing; dethroning |
| depravity | extreme corruption; wickedness; V. deprave |
| deprecate | express disapproval of; deplore; protest against; belittle; ADJ. deprecatory |
| depreciate | lessen in value; belittle; represent as of little value |
| depredation | plundering; destruction |
| deranged | insane |
| s institute | organization for a special purpose; V: establish |
| s institution | instituting; (building for the) organization; established custom, practice, or relationship in a society; mental hospital; Ex. institution of marriage |
| s institutionalize | make into an institution; put or confine in an institution |
| derelict | negligent; (of someone) neglectful of duty; (of something) deserted by an owner; abandoned; N: abandoned property; homeless or vagrant person |
| s dereliction | neglect of duty; abandonment |
| deride | ridicule; treat with contempt; make fun of; OP. respect |
| derision | ridicule; ADJ. derisive; CF. derisory |
| derivative | unoriginal; obtained from another source; Ex. derivative prose style; N. |
| s derivation | deriving; origin or source of something; Ex. the derivation of the word |
| dermatologist | one who studies the skin and its diseases |
| s acne | skin disease (on the face) |