'Quaint' meant 'known' in Latin, 'clever' in French, then 'charmingly old-fashioned' in English. Total reinvention.
Attractively unusual or old-fashioned; pleasingly or strikingly old-fashioned or unfamiliar.
From Middle English queinte, coint (clever, skilled, elegant, strange), from Old French cointe (knowledgeable, well-informed, clever, elegant), from Latin cognitus (known, recognised), past participle of cognōscere (to learn, to come to know), from PIE *ǵneh₃- (to know). The semantic journey of quaint is one of the most dramatic in English: it begins at PIE *ǵneh₃- meaning to know — the same root that produced know, gnosis, cognition, and narrative. Latin cognitus (known) became Old French cointe (clever
Chaucer used 'queynte' extensively in both its 'clever/elegant' sense and as a punning euphemism. The word has undergone one of the most dramatic semantic journeys in English: from Latin 'known' to Old French 'clever' to Middle English 'ingenious/elegant' to early Modern English 'strange/unusual' to modern 'charmingly old-fashioned.' Each stage shifted further from the original sense of knowing.