c. 1400, requiten, "make return for, repay" (for good or ill), from Old French requiter or formed in English from re- "back" + Middle English quite "clear, pay up," an early variant of quit (v.) preserved in this word; in early use requite was often requit. Related: Requited; requiting.

"return for some service, kindness, etc.; act of requiting" for good or ill, 1570s, from requite + -al (2).

"capable of being compensated," 1660s, from French compensable (16c.), from compenser, from Latin compensare (see compensate). Middle English had the simple verb compense "make up for (something), counterbalance, compensate; requite; satisfy (a need)," from Latin compensus, but compensate seems to have replaced it. The Old French adjective compensable meant "to consider, ponder."

"requite, repay, or return in kind," 1610s, from Latin retaliatus, past participle of retaliare "pay back in kind," from re- "back" (see re-) + Latin talio "exaction of payment in kind," from or influenced by talis "suchlike" (see that). Originally of kindness, civility, etc., but by 1630s of injury, ill-treatment, etc. (now the usual sense). Intransitive sense is from 1650s. Related: Retaliated; retaliating.

c. 1300, obligacioun, "a binding pledge, commitment to fulfill a promise or meet conditions of a bargain," from Old French obligacion "obligation, duty, responsibility" (early 13c.) and directly from Latin obligationem (nominative obligatio) "an engaging or pledging," literally "a binding" (but rarely used in this sense), noun of action from past-participle stem of obligare "to bind, bind up, bandage," figuratively "put under obligation" (see oblige). The notion is of binding with promises or by law or duty.

The meaning "that which one is bound or obliged to do, especially by moral or legal claims a duty" is from c. 1600. That of "state or fact of being bound or constrained by gratitude to requite benefits, moral indebtedness," also is from c. 1600. Related: Obligational.