recreant (adj.)youdaoicibaDictYouDict[recreant 词源字典]
c. 1300, "confessing oneself to be overcome or vanquished," from Old French recreant "defeated, vanquished, yielding, giving; weak, exhausted; cowardly," present participle adjective from recroire "to yield in a trial by combat, surrender allegiance," literally "believe again;" perhaps on notion of "take back one's pledge, yield one's cause," from re- "again, back" (see re-) + croire "entrust, believe," from Latin credere (see credo).
Non sufficit ... nisi dicat illud verbum odiosum, quod recreantus sit. [Bracton, c. 1260]
Meaning "cowardly" in English is from late 14c. Meaning "unfaithful to duty" is from 1640s.[recreant etymology, recreant origin, 英语词源]
recreant (n.)youdaoicibaDictYouDict
"one who yields in combat, one who begs for mercy, one who admits defeat," early 15c., hence "coward, faint-hearted wretch;" from recreant (adj.) and from Old French recreant as a noun, "one who acknowledges defeat, a craven, coward, renegade, traitor, wretch." In English, sense of "apostate, deserter, villain" is from 1560s.