quaint

This little root hides one of the most dramatic meaning-shifts in English. It begins with Latin cognōscere ('to get to know, to recognize') — co- ('thoroughly') + gnōscere ('to know'). Its past participle cognitus ('known, recognized') traveled through Old French, where it was worn down to cointe, an adjective meaning 'knowledgeable, skilled, clever.'

That French cointe is the direct ancestor of English quaint. And here is the surprise: quaint did not always mean 'charmingly old-fashioned.' In Middle English it meant 'clever, cunning, skillfully made' — a quaint device was an ingenious one. Over centuries the sense drifted: clever → elaborate and fancy → curiously old-fashioned → the modern 'attractively old-fashioned, charmingly odd.' A word that once praised cleverness now describes a sleepy village with cobbled streets. The 'know' core is almost invisible today, but it is still there: quaint things are recognizably of another time.

The family's clearer members keep the 'know' sense on the surface. Acquaint = ad- ('to') + the cointe stem = 'to bring (someone) to knowledge of' — to make familiar. From it grow acquaintance (a person you know slightly; slight knowledge), acquainted, unacquainted, well-acquainted, reacquaint, and acquaintanceship. All of them are about the degree to which you know someone or something.

A cousin sits one step away: cognizant ('aware, fully informed') comes straight from the same cognōscere through its Latin form, keeping the un-disguised 'know' meaning. It is the formal twin of 'aware,' and the bridge that shows quaint and acquaint really do share the 'knowing' root, however far quaint has wandered.