| Term | Definition |
| altruism | n. unselfish devotion to others, philanthropy, benevolence |
| altruist | n. one unselfishly devoted to others, philanthropist |
| altruistic | adj. generous, unselfish, devoted to others |
| aluminum | n. malleable silvery metallic element used in alloys and in the manufacture of lightweight objects (Chemistry) |
| amalgam | n. alloy, mixture of metals (commonly used in dentistry for fillings) |
| amalgamate | v. combine; unite; combine |
| amalgamated | v. combine; unite; combine |
| amateur | adj. not professional, novice |
| ambidextrous | adj. using both hands with equal ease |
| ambiguity | n. vagueness; lack of clarity |
| ambiguous | adj. open to dispute, having many possible interpretations; obscure, vague |
| ambition | n. aspiration, hope |
| ambitious | adj. aspiring, desirous of success ; requiring great effort |
| ambivalence | n. state of having both positive and negative feelings towards a subject |
| ambivalent | adj. having both positive and negative feelings towards a subject |
| amble | v. walk at an easy pace |
| ambushed | v. hide in order to make a surprise attack |
| ameliorate | v. improve, better; get better, improve oneself |
| amelioration | n. improvement, renovation, betterment |
| amenable | adj. agreeable, responsive, tractable; accountable, responsible; open to criticism or examination |
| amend | v. change, alter; improve; improve oneself |
| amendment | n. correction, revision; alteration, change |
| amiability | n. friendliness; pleasantness, agreeableness; hospitality, cordiality |
| amiable | adj. genial, likable; friendly; pleasant |
| amicable | adj. friendly, cordial, amiable, sociable |
| amity | n. friendship, friendly ties; mutual understanding and peaceful relations; accord |
| amnesia | n. condition caused by illness or injury and characterized by forgetfulness |
| amnesty | n. clemency, pardon v. pardon, grant clemency |
| amorphous | adj. shapeless, formless; changeable, mutable |
| amorphousness | n. state of formlessness; mutable state |
| amortize | v. settle a debt through periodic payments to a creditor or to a sinking fund; pay off a debt gradually, become depreciated (also amortise) |
| amphibian | n. cold-blooded vertebrate animal able to live both on land and water |
| amphibious | n. cold-blooded vertebrate animal able to live both on land and water |
| amplification | n. strengthening, reinforcement; enlarging |
| amplified | adj. made stronger; reinforced; aggrandized |
| amplifier | n. device which amplifies or increases (power, current, etc.) |
| amplify | v. strengthen, reinforce, make stronger; expand; increase the amplitude |
| amulet | n. small trinket worn as charm against evil eye |
| amuse | v. entertain; cause to laugh |
| amused | adj. entertained; pleasantly occupied; having one's attention diverted in an agreeable manner |
| amusement | n. entertainment; pleasure; fun, play |
| amusing | n. humorous, entertaining, funny |
| anachronism | n. assigning of a person or event to the wrong time period; something that is obsolete or out of date |
| anachronistic | adj. obsolete, out of date; not properly dated, not assigned to the correct time period (of a person, object or event) |
| anagram | n. transposition of the letters of a word to make a new word |
| analgesia | n. absence of pain, insensitivity to pain |
| analgesic | adj. pain-killing, pain-reducing, anaesthetic |
| analogous | adj. parallel; similar, comparable |
| analogue | n. something which has a similarity to something else |
| analysis | n. process of breaking down a subject and studying it; examination |
| analytical | adj. pertaining to analysis; critical |
| anarchist | n. advocate of anarchy (social movement that objects to laws and government) |
| anarchy | n. lawlessness, absence of laws and government |
| anathema | n. ban, excommunication; despised person or thing |
| anatomical | adj. pertaining to anatomy, of the body structure of organisms |
| ancestor | n. forefather, progenitor |
| ancestry | n. family origin, genealogy; line of descent |
| anchor | v. attach firmly, fasten tightly; drop an anchor (from a boat) |
| anecdotal | adj. pertaining to an anecdote (short narrative describing an interesting or amusing incident) |
| anecdote | n. short narrative describing an interesting or amusing incident |
| anemia | n. condition caused by a lack of red blood cells and characterized by weakness and breathlessness (Pathology); weak, powerless, lack of vitality |
| anesthetic | n. substance which reduces sensitivity to pain (i.e. ether or halothane) |
| anguish | n. agony, torment; anxiety, fear |
| angular | adj. pointed; having angles; bony; stiff |
| angularity | n. stiffness, lack of grace; boniness, gauntness; angular outlines or characteristics |
| anhydrous | adj. lacking water |
| animate | v. make alive; arouse; inspire; excite |
| animated | adj. alive; lively, dynamic, vigorous, energetic; functioning in a way that resembles a live being (especially regarding animated cartoon characters) |
| animatedly | adv. vigorously, energetically, in a lively manner |
| animation | n. vitality; wakefulness; creation of cartoons |
| animosity | n. resentment; hostility |
| annals | n. historical records, chronicles, archives |
| annexation | n. addition, appending, attachment; territorial extension; connection, union |
| annihilate | v. destroy, demolish; exterminate |
| annihilation | n. destruction, ruin; extinction, extermination |
| annotate | v. provide analytical notes; make footnotes; explain |
| annotated | adj. explained, elucidated, containing explanatory comments |
| annotation | n. comment or explanation added to a text; comment or remark added to a computerized document (Computers); additional information about a part or feature of a computer program (Computers) |
| announce | v. declare; proclaim |
| announced | v. declared; proclaimed |
| announcement | n. declaration; notice |
| annoy | v. bother, harass, irritate |
| annoyance | n. harassment; bother, nuisance; sorrow, grief |
| annoyed | adj. angry, irritated, vexed, exasperated |
| annoying | adj. harassing, bothersome |
| anodized | v. coat metal with a protective layer of oxide using electrolytic means (also anodise) |
| anomalous | adj. abnormal, irregular, unusual, exceptional |
| anomaly | n. exception; deviation; strangeness; something which is out of the ordinary |
| anonymity | n. condition of being unknown, namelessness |
| anonymous | adj. nameless, of an unknown person |
| antagonism | n. hostility; conflict |
| antagonistic | adj. hostile, unfriendly |
| antagonize | v. cause to hate, make an enemy of; cause hostility, provoke antagonism; oppose, counteract (also antagonise) |
| Antarctic | n. region of the South Pole |
| antecedent | adj. preceding, prior, previous, earlier |
| antedate | v. precede in time, predate; assign to a date prior to that of the actual occurrence |
| antenna | n. conductor, signal receiver; feeler, sensory organ in insects and some arthropods |
| anthem | n. hymn; patriotic song |
| anthology | n. reader; collection; compilation; collection of literary works |
| anthropologist | n. expert in anthropology (study of the development of the human race) |
| antibiotic | adj. kills bacteria, working against infectious diseases |
| antibiotics | n. type of medication used to treat infectious diseases |
| antibody | n. protein in the blood which reacts to infectious agents |
| antic | n. prank, trick, mischief; funny movement, buffoonery |
| anticipate | v. expect, predict; precede; hurry and come before |
| anticipated | adj. expected, foreseen, predicted, envisioned |
| anticipation | n. expectation, hope; intuition, foreknowledge |
| anticipatory | adj. expressing anticipation, preparatory, expectant |
| anticlimax | n. abrupt move from a serious or tense situation to an absurd situation |
| antidote | n. remedy; medicine that works against the effects of poison |
| antigen | n. foreign substance which stimulates the production of antibodies when introduced into a living organism |
| antihistamine | n. in the drug which counteracts histamine body (treatment for allergies) |
| antipathy | n. aversion, enmity, loathing, animosity |
| antiquated | adj. out-of-date, old-fashioned, outmoded, obsolete |
| antique | n. antique object, old object; antique style (in art) |
| antiseptic | n. substance which destroys microorganisms which produce sepsis |
| antithesis | n. opposite, contrast |
| antithetical | adj. contrary, opposed, involving antithesis |
| antitoxic | adj. counteracting toxic influences, containing antitoxins |
| anvil | n. heavy block on which metal is hammered |
| anxiety | n. fear, worry; eagerness |
| anxiousness | n. anxiety, apprehension, worry; intense desire, eagerness |
| aorta | n. main artery of the body |
| apathetic | adj. lethargic, indifferent |
| apathy | n. indifference, disinterest |
| apex | n. highest point, climax, uppermost point; lowest part of the root of a tooth (Dentistry) |
| aphorism | n. concise saying which expresses a general truth |
| aphoristic | adj. of aphorisms, of maxims |
| aplomb | n. complete self-confidence, composure, self-assurance |
| apocrypha | n. Old Testament books not included in the Bible |
| apocryphal | adj. doubtful; not genuine; pertaining to the Apocrypha (Old Testament books not included in the Bible) |
| apolitical | adj. having no interest or involvement in political affairs; not politically influential |
| apologist | n. theologian who speaks in defense of Christianity; person who argues in favor of something |
| apologize | v. express regret, express sorrow for one's actions |
| apology | n. expression of regret or sorrow; defense, justification |
| apostasy | n. heresy; disloyalty |
| apostate | adj. guilty of apostasy (abandonment of religious vows or values) n. one who is guilty of committing heresy; traitor |
| apostrophe | n. punctuation mark used to indicate omission of letters or possession; digression in a discourse to someone not present |
| appalling | adj. shocking, terrible, frightening, horrifying |
| apparatus | n. device; system |
| apparent | adj. obvious; ostensible, pretended |
| apparition | n. ghost, spirit, manifestation |
| appeal | v. plead; request; petition for a new trial or judgement |
| appealing | adj. begging; attractive; interesting |
| appearance | n. act of coming into view; impression, semblance |
| appease | v. soothe, ease, bring peace; relieve, satisfy |
| appeasement | n. easing, soothing; relief |
| appeasing | v. soothe, ease, bring peace; relieve, satisfy |
| appendix | n. small sac attached to the intestines; addendum |
| appetite | n. desire, hunger |
| appetizer | n. small portion of food which is served before the main meal to stimulate the appetite; hors d'oeuvre, light food served as an appetizer before a meal (also appetiser) |