A water bird with dark feathers and a white face, common on lakes and ponds; also informal slang for an eccentric or silly person.
From Middle English 'cote,' possibly from Old Norse 'út' (out) or Low German origins. The bird name dates back at least to the 14th century; the slang use for a foolish person developed later.
Coots are funny-looking birds—they're not actually ducks though people confuse them, and the name became slang for 'foolish person' probably because their jerky movements seemed silly to old-time observers.
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