Meaning

noun an adequate quantity; a quantity that is large enough to achieve a purpose

adjective sufficient for the purpose

adverb as much as necessary; ; (`plenty' is nonstandard)

originFrom Middle English ynogh, from Old English ġenōg (“enough”), from Proto-Germanic *ganōgaz (“enough”) (compare Scots eneuch, West Frisian genôch, Dutch genoeg, German genug, Low German (ge)noog, Danish nok, Swedish nog, Icelandic nógur), from *ganuganą 'to suffice' (compare Old English ġeneah), or from *ga- + an unattested *nōgaz, probably ultimately from Proto-Indo-European *h₂eh₂nó(n)ḱe (“he…

Etymology from Wiktionary, CC BY-SA 3.0