Galore
early 17th century: from Irish go leor, literally ‘to sufficiency’.
wiktionary
Borrowed from Irish go leor and Scottish Gaelic gu leòr, gu leòir(“till sufficient, enough, plenty”) (compare Manx dy liooar), from Irish go, Scottish Gaelic gu(“to; till, until”) + Irish leor, Scottish Gaelic leòr(“ample, sufficient”); go, gu are derived from Old Irish co, cu(“with”), ultimately from Proto-Indo-European *ḱóm(“beside, by; near; with”); while leor, leòr are from Old Irish leor, from lour(“enough, sufficient”), ultimately from Proto-Indo-European *leh₂w-(“to gain; to seize; a benefit; a prize”). [1]
etymonline
galore (adv.)
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.