coy

This little adjective started life meaning something closer to “quiet” than “flirty.” In Old French, coi was the sort of word you’d use for a placid room, a still pond, or a person who wasn’t making a scene; Middle English borrowed it and kept the hush. Then the meaning slid from “quiet” to “shy” to the modern “I know something, but I’m not telling,” which is exactly the sort of social smirk languages love to hide in plain sight. It’s a close cousin of quiet, quit, quite, and quietus — all that same calm Latin family, now scattered across English like relatives who moved to different cities and changed jobs. By the time you get to a 1961 “coy” meaning of reluctance to commit, the word has gone from still water to raised eyebrow. A tiny word, really, but it carries the whole history of people trying not to speak up.