1630s, "act of condescending," from French condescendance, from condescendre"to consent, give in, yield," from Latin condescendere "to let oneself down" (see condescend). Related: Condescendency.
1786, from verbal phrase (attested by 1711) in reference to one who "ruins" the "fun;" see spoil (v.) + sport (n.). Compare Chaucer's letgame "hinderer of pleasure" (late 14c.), from obsolete verb let (Middle English letten) "hinder, prevent, stop" (see let (n.)). Another old word for it was addle-plot "person who spoils any amusement" (1690s; see addle).
early 15c., "acceptance, reception, approval," from Latin admissionem (nominative admissio) "a letting in," noun of action from past-participle stem of admittere "admit, give entrance; grant an audience," of acts, "let be done, allow, permit," from ad "to" (see ad-) + mittere "let go, send" (see mission). Meaning "an acknowledging" is from 1530s. Literal sense of "act of allowing to enter, admittance," is from 1620s. As short for admission price, by 1792.