effervescent (adj.)

1680s, from Latin effervescentem (nominative effervescens), present participle of effervescere "to boil up, boil over," from assimilated form of ex "out" (see ex-) + fervescere "begin to boil," from fervere "be hot, boil" (from PIE root *bhreu- "to boil, bubble, effervesce, burn"). Figurative meaning "exuberant" is from 1833.