mid-15c., in law, "one who brings suit" (a sense now in complainant), agent noun from complain (v.). From 1520s as "a fault-finder, a grumbler."
late 15c., "a covenant or agreement," from French convenance "convention, agreement, convenience," from convenant, present participle of convenir "to come together; join, fit, suit" (see convene). Meaning "conventional propriety" is from 1847.
c. 1600, "action of adapting (something to something else)," from French adaptation, from Late Latin adaptationem (nominative adaptatio), noun of action from past-participle stem of adaptare "to adjust," from ad "to" (see ad-) + aptare "to join," from aptus "fitted" (see apt).
Meaning "condition of being adapted, state of being fitted to circumstances or relations" is from 1670s. Sense of "modification of a thing to suit new conditions" is from 1790. Biological sense "variations in a living thing to suit changed conditions" first recorded 1859 in Darwin's writings.
in law, a joint respondent, one proceeded against along with another or others, 1857, from co- + respondent. "[S]pecifically, in Eng. law, a man charged with adultery, and made a party together with the wife to the husband's suit for divorce." [Century Dictionary].
1640s, "during, in the process of, for the time of the continuance of," a preposition formed on the model of French pendant "during," literally "hanging," present participle of pendere "to hang, cause to hang" (from PIE root *(s)pen- "to draw, stretch, spin").
The meaning is patterned on "not decided" as a secondary sense of Latin pendente (literally "hanging") in the legal phrase pendente lite "while the suit is pending, during the litigation" (with the ablative singular of lis "suit, quarrel"). The use of the present participle before nouns caused it to be regarded as a preposition. As an adjective from 1797.
in law, formal notice to a plaintiff that the prosecutor will not continue a suit, Latin, literally "to be unwilling to pursue." The derived verb nolle-pross "to abandon (a prosecution, etc.) by nolle prosequi" is attested from 1880. Latin nolle "be unwilling" is from ne "not" + velle "will."
