c.1225, "free, clear," from O.Fr.
quite "free, clear," from L.
quietus "free" (in M.L. "free from war, debts, etc."), also "calm, resting" (see
quiet). The verb is first attested c.1300, "to set free, redeem" (usually of a debt or suspicion); sense of "leave" is attested from c.1390; that of "to leave (a place)" is from 1603; that of "stop" (doing something) is from 1641. Meaning "to give up" is from 1440;
quitting time is from 1835;
quitter as an insult is 1881, Amer.Eng.
Quits "even" (with another) is from 1663.