A fool or simpleton, used in dialectal or archaic English; also a nonsensical act or behavior.
Possibly related to gammon (nonsense) or dialectal English; part of a family of words describing foolish behavior and people.
Old English is full of colorful insults for foolish people—gammock joins a crowd with 'nincompoop,' 'blithering idiot,' and 'loon,' showing how every generation invents its own creative ways to mock foolishness.
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