Middle English quenchen, "to extinguish, put out" (heat, light, fire, also of desire, hunger, thirst), also figurative, "to bring to naught, eliminate, render ineffectual" (c. 1200), Old English acwencan "to quench" (of fire, light), from Proto-Germanic *kwenkjanan, probably a causative form from the source of Old English cwincan "to go out, be extinguished," Old Frisian kwinka. No certain cognates outside Germanic; perhaps a substratum word. Especially "to cool or extinguish by means of cold water," hence "to drench in water" (late 15c.). Related: Quenched; quenching.
"to put out, quench, stifle," 1540s, from Latin extinguere/exstinguere "quench, put out (what is burning); wipe out, obliterate," from ex "out" (see ex-) + stinguere "quench," apparently an evolved sense from PIE *steig- "to prick, stick, pierce" (see stick (v.)). But see distinguish (v.). Related: Extinguished; extinguishing.
early 15c., "annihilation," from Latin extinctionem/exstinctionem (nominative extinctio/exstinctio) "extinction, annihilation," noun of action from past-participle stem of extinguere/exstinguere "quench, wipe out" (see extinguish). Originally of fires, lights; figurative use, the wiping out of a material thing (a debt, a person, a family, etc.) from early 17c.; of species by 1784.
"wasting away of the body," 1650s, Modern Latin, from Greek marasmos "a wasting away, withering, decay," from marainein "to quench, weaken, wither," from PIE root *mer- "to rub away, harm," but Beekes has doubts about this. "The term is usually restricted to cases in which the cause of the wasting is obscure" [Century Dictionary]. Maras (n.), evidently in the same sense, is attested from mid-15c. Related: Marasmic.
early 15c., "extinguished, quenched," from Latin extinctus/exstinctus, past participle of extinguere/exstinguere "to put out, quench; go out, die out; kill, destroy" (see extinguish). Originally of fires; in reference to the condition of a family or a hereditary title that has "died out," from 1580s; of species by 1690s. Shakespeare uses it as a verb. Compare extinction.
1610s, from French amarante, from Latin amarantus/amaranthus, from Greek amarantos, name of a mythical unfading flower, literally "unfading, undecaying," from a- "not" (see a- (3)) + stem of marainein "die away, waste away, decay, wither; quench, extinguish," from PIE root *mer- "to rub away, harm" (also "to die" and forming words referring to death and to beings subject to death).
In classical use, a poet's word for an imaginary flower that never fades. It was applied in botany to a genus of ornamental plants 1550s. The ending has been influenced by plant names from unrelated Greek -anthos "flower."
early 15c., "to drive away, remove, quench" (a sense now obsolete), from Old French repeller and directly from Latin repellere "to drive back," from re- "back" (see re-) + pellere "to drive, strike" (from PIE root *pel- (5) "to thrust, strike, drive").
The sense of "encounter (an invader, etc.) with effectual resistance, resist, oppose" is from mid-15c. The meaning "to affect (a person) with distaste or aversion" is by 1817. Related: Repelled; repelling.
Middle English slaken, from late Old English sleacian, slacian "become slack or remiss; relax an effort" (intransitive); "delay, retard" (transitive), from slæc "lax" (see slack (adj.), and compare Middle Dutch, Middle Low German slaken).
The transitive sense of "make slack, loosen" (ropes, a bridle, etc.) is from late 12c. The sense of "allay, diminish in force or intensity, quench, extinguish" is from late 13c. in reference to fire, c. 1300 in reference to thirst, hunger, desire, wrath, lust, etc. The notion is "make slack or inactive." Related: Slaked; slaking.