mid-15c., from Middle French exubérant and directly from Latin exuberantem (nominative exuberans) "overabundance," present participle of exuberare "be abundant, grow luxuriously," from ex- "thoroughly" (see ex-) + uberare "be fruitful," related to uber "udder," from PIE root *eue-dh-r- (see udder). Related: Exuberantly; exuberate; exuberating.