faintly (adv.)youdaoicibaDictYouDict[faintly 词源字典]
c. 1300, "dispiritedly, timidly, half-heartedly;" early 14c. "feebly, wearily, without vigor;" from faint (adj.) + -ly (2). Meaning "indistinctly" is from 1580s. Also in Middle English, "deceitfully, hypocritically, falsely" (mid-14c.).[faintly etymology, faintly origin, 英语词源]