fervent (adj.)youdaoicibaDictYouDict[fervent 词源字典]
mid-14c., from Old French fervent "fervent, ardent" (12c.), from Latin ferventem (nominative fervens) "boiling, hot, glowing," figuratively "violent, impetuous, furious," present participle of fervere "to boil, glow," from PIE root *bhreuə- "to boil, bubble" (see brew (v.)). The figurative sense of "impassioned" is first attested c. 1400. Related: Fervency; fervently.[fervent etymology, fervent origin, 英语词源]