jollyyoudaoicibaDictYouDict[jolly 词源字典]
jolly: [14] Old French jolif meant ‘pleasant, merry, festive’ (it has been speculated that it may have been derived from jól, the Old Norse term for the midwinter festival, to which English yule is closely related). English took the adjective over, and whereas in French (the modern form is joli) it has come to mean ‘pretty’, in English it kept closer to the original sense ‘merry’.
=> yule[jolly etymology, jolly origin, 英语词源]
jolly (adj.)youdaoicibaDictYouDict
c. 1300 (late 13c. as a surname), from Old French jolif "festive, merry, amorous, pretty" (12c.) of uncertain origin (cognate with Italian giulivo "merry, pleasant").

Perhaps a Germanic loan-word from a source akin to Old Norse jol "a winter feast" (see yule), or from Latin gaudere "to rejoice," from PIE *gau- "to rejoice" (see joy). For loss of -f, compare tardy, hasty. Related: Jollily; jolliness.