exuberant (adj.)

Old English udder "milk gland of a cow, goat, etc.," from Proto-Germanic *udr- (source also of Old Frisian uder, Middle Dutch uyder, Dutch uijer, Old High German utar, German Euter, and, with unexplained change of consonant, Old Norse jugr), from PIE *eue-dh-r "udder" (source also of Sanskrit udhar, Greek outhar, Latin uber "udder, breast").

1630s, "an overflowing," from French exubérance (16c.), from Late Latin exuberantia "superabundance," abstract noun from exuberare "be abundant, grow luxuriously" (see exuberant). Usually figurative in English, especially of joy, happiness, etc. Exuberancy attested from 1610s.

word-forming element, in English meaning usually "out of, from," but also "upwards, completely, deprive of, without," and "former;" from Latin ex "out of, from within; from which time, since; according to; in regard to," from PIE *eghs "out" (source also of Gaulish ex-, Old Irish ess-, Old Church Slavonic izu, Russian iz). In some cases also from Greek cognate ex, ek. PIE *eghs had comparative form *eks-tero and superlative *eks-t(e)r-emo-. Often reduced to e- before -b-, -d-, -g-, consonantal -i-, -l-, -m-, -n-, -v- (as in elude, emerge, evaporate, etc.).