| a fortiori | adv. | all the more, for an even stronger reason | Latin | |
| a taunto | adj. | of a ship with all sails set; prepared | ||
| a tergo | adv. | from behind | Latin | |
| abaft | prep. | aft of, behind; towards the rear | nautical | |
| abgeschmackt | adj. | tasteless, vulgar | ||
| abigail | n. | lady’s maid | ||
| abject | adj. | wretched, miserable; despicable | ||
| abjectly | adv. | shamefully, in a completely undignified manner | ||
| ablation | n. | removal; loss of surface (as of rocks or a glacier) through erosion or other natural process | ||
| ablution | n. | washing of the hands, face, etc. | ||
| abomination | n. | object of disgust or hatred, detestable thing; feeling of extreme loathing | ||
| abreact | v. | to release a repressed emotion through the process of re-experiencing it | ||
| abscissa | n. | x-coordinate of point in Cartesian plane system | ||
| abscission | n. | natural separation of parts from a plant; cutting off | botany | |
| abseil | v. | to rappel | ||
| absit omen | int. | said when referring to bad thing in order to forestall its arrival, similar to ‘God forbid’ (Latin for ‘may this omen be absent’) | Latin | |
| absquatulate | v. | to flee, to abscond, to leave hurriedly or secretly | ||
| abstruse | adj. | hard to understand; recondite | ||
| abulia | n. | loss or severe reduction of volition, as symptom of mental disorder | ||
| acatalepsy | n. | incomprehensibility, Skeptic teaching that only partial perception or plausible conceptions of truth are possible | ||
| accidence | n. | study of word inflections, the basics of grammar; rudiments of a subject | ||
| accidie | n. | sloth, torpor; indifference, esp. in religious duties | ||
| accipitrine | adj. | of or related to a hawk; raptor-like | ||
| acclivity | n. | rising slope | ||
| according to Cocker | adv. | according to Hoyle, strictly by the rules | British | |
| accoucheur | n. | male midwife or obstetrician | ||
| accouter | v. | to equip, to outfit | ||
| accumb | v. | to recline while dining as did the ancient Romans | ||
| accumbent | adj. | reclining, lying against something; dining while reclining | ||
| accumber | v. | to overwhelm, to crush, to burden | obsolete | |
| Aceldama | n. | field of bloodshed (from the field bought by Judas with his thirty pieces of silver) | ||
| acephalous | adj. | headless; leaderless | ||
| acequia | n. | irrigation ditch | ||
| acerbly | adv. | sourly, bitterly | ||
| achalasia | n. | inability of a circular muscle, esp. of the esophagus or rectum, to relax, causing the structure above the muscular constriction to widen | ||
| acidulate | v. | to make sour; to acidify | ||
| acidulous | adj. | slightly sour | ||
| acromegaly | n. | disease causing growth of head, hands and feet due to disfunction of pituitary gland | ||
| acroter | n. | pedestal at apex or bases of pediment, upon which statue or ornament (an acroterium or acroterion) is placed | ||
| actantial | adj. | of a mode of semiotic analysis whereby the action is broken down into various structural roles performed | ||
| actinic | adj. | of or relating to radiation causing chemical or biological effects; of light which causes exposure of monochrome film | ||
| acuity | n. | sharpness, keenness | ||
| ad libitum | adj. | as much as one wishes, without restriction, ‘according to pleasure’ | Latin | |
| addle | v. | to make (eggs) rotten | ||
| adduce | v. | to cite, to present as evidence | ||
| adit | n. | horizontal opening into a mine | ||
| adither | adj. | flustered, in a state of confusion | ||
| adminicle | n. | document attesting to existence or contents of another document | ||
| admix | v. | to mix together, to commingle | ||
| adumbrate | v. | to outline; to foreshadow; to faintly indicate; to overshadow, to partially conceal |
