Having hackles raised or standing up; roughened or combed with a hackle tool; angered or with feathers or hair standing on end.
From hackle (to comb or card fibers, or feathers on a bird's neck that rise when angered) + -ed (past tense/adjective suffix). The word comes from Old Norse/Germanic roots related to combing and rough textures.
When you describe someone as 'hackled up,' you're using a word that originally described how roosters puff up their feathers when angry—animals inspired our metaphors for human emotion centuries ago!
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