source: Kirei Kotomine Love Story...Kind of..😂 | Anime Amino

verb no object

feel or show great joy or delight:

｟文｠ 〈人が〉 «…を» 喜ぶ «at, over, in» ; 〖to do/～ that節〗 …して［…ということに］喜ぶ, 歓喜する, うれしがる

e.g. he rejoiced in her spontaneity and directness

e.g. he rejoiced when he saw his friend alive.

with object archaic cause joy to:

｟ややまれ｠ ; 〖通例be ～d〗 «…に/…して» 喜ぶ «at, by/to do» .

e.g. I love to rejoice their poor Hearts at this season.

rejoicer noun

Middle English (in the sense ‘cause joy to’): from Old French rejoiss-, lengthened stem of rejoir, from re- (expressing intensive force) + joir ‘experience joy’.