ラテン語のquietus（静かな、平和な）が語源で、語源的にはquitと同じ。 free from interference（干渉から解放される）、free from trouble（トラブルから解放される）から派生し、後に自由な、解放された、借金がチャラになったという意味で使われる。また、仕事を辞めるという意味の動詞の派生。acquit、requiteと比較される。
英語の語源
quit
quit: [13] Quit comes from the same ultimate source as quiet – Latin quiētus. This originally meant simply ‘quiet, calm’, but in medieval Latin it developed a wider range of senses, including ‘unharmed’ and ‘free’. From it was derived the verb quiētāre ‘set free, discharge’, which reached English via Old French quiter. The derived forms acquit and requite [16] come from the same source, and quite is essentially the same word as quit. => quiet
quit (v.)
c. 1200, "to repay, discharge" (a debt, etc.), from Old French quiter "clear, establish one's innocence;" also transitive, "release, let go, relinquish, abandon" (12c.), from quite (see quit (adj.)).
Meaning "to reward, give reward" is mid-13c., that of "take revenge; to answer, retort" and "to acquit oneself" are late 14c. From c. 1300 as "to acquit (of a charge), declare not guilty." Sense of "leave, depart" is attested from c. 1400; that of "stop" (doing something) is from 1640s. Meaning "to give up, relinquish" is from mid-15c. Related: Quitted; quitting. Quitting time is from 1835.
quit (adj.)
c. 1200, "free, clear" (of debt, etc.), from Old French quite, quitte "free, clear, entire, at liberty; discharged; unmarried," from Medieval Latin quitus, quittus, from Latin quietus "free" (in Medieval Latin "free from war, debts, etc."), also "calm, resting" (see quiet (adj.)).
例文
1. Well，parenthetically，I was trying to quit smoking at the time.
うん、一言、私はその時タバコをやめようと努力していた。
2.He quit his job as an office boy in Athens.
彼はアテネで事務所の雑用係として働いていた仕事を辞めた。
3.He did not quit as France 's prime minister of his own accord.
彼がフランスの首相を辞任したのは自発的ではない。
4.She quit school as soon as she had taken her GCSES.
彼女は普通中等教育証明書を手に入れると学校を休んだ。
5.Police were called when he refused to quit the building.