"in or farther toward the back part (of a ship)," as opposed to forward, 1590s, from Middle English on baft (late 13c.) "back, behind, to the rear," from Old English on bæftan. For first element, see a- (1). The second component is itself a compound of be "by" (see by) and æftan "aft" (see aft). The word has been saved by the sailors (the stern being the "after" part of a vessel), the lubbers having left it in Middle English.

1590s, "a wandering, act of straying," from Latin aberrationem (nominative aberratio) "a wandering," noun of action from past-participle stem of aberrare "to wander out of the way, lose the way, go astray," literally and figuratively, from ab "off, away from" (see ab-) + errare "to wander, stray, roam, rove" (see err). Meaning "deviation from the normal type" is attested by 1735.

1590s, "a swallowing up" (now obsolete), from Latin absorptionem (nominative absorptio) "a swallowing," noun of action from past-participle stem of absorbere "swallow up" (see absorb). From 1714 specifically of "disappearance by assimilation into something else."

1590s, "remote from comprehension," from French abstrus (16c.) or directly from Latin abstrusus "hidden, concealed, secret," past participle of abstrudere "conceal, hide," literally "to thrust away," from assimilated form of ab "off, away from" (see ab-) + trudere "to thrust, push" (from PIE root *treud- "to press, push, squeeze;" see threat). Related: Abstrusely; abstruseness.

also accoutre, "to dress or equip" (especially in military clothing and gear), 1590s, from French acoutrer, earlier acostrer (13c.) "arrange, dispose, put on (clothing)," probably originally "sew up," from Vulgar Latin *accosturare "to sew together, sew up," from Latin ad "to" (see ad-) + *consutura "a sewing together," from Latin consutus, past participle of consuere "to sew together," from con- (see com-) + suere "to sew" (from PIE root *syu- "to bind, sew"). The English spelling reflects the 16c. French pronunciation. Related: Accoutered; accoutred; accoutering; accoutring.

"person charged with a crime," 1590s, from past participle of accuse (v.).

1590s, "act of acknowledging," from acknowledge + -ment. "An early instance of -ment added to an orig. Eng. vb." [OED]. Meaning "token of due recognition" is recorded from 1610s.

1590s, "putting forth activity, active," present-participle adjective from act (v.). Meaning "performing temporary duties" is from 1797.

"furnishing sufficient grounds for a (legal) action," 1590s; from action + -able. Related: Actionably.

1590s, "perform" (a sense now obsolete), from Medieval Latin actuatus, past participle of actuare "perform, put into action," from Latin actus "a doing" (from PIE root *ag- "to drive, draw out or forth, move"). The sense of "put into action, inspire with activity" is from 1640s. Related: Actuated; actuating.