1670s, from Irish go leór, and equivalent Scottish Gaelic gu leóir "sufficiently, enough," from Old Irish roar "enough," from Proto-Celtic *ro-wero- "sufficiency." The particle go/gu usually means "to," but it also is affixed to adjectives to form adverbs, as here. Often used in English with the force of a predicate adjective.[galore etymology, galore origin, 英语词源]