A stupid or foolish person; a blockhead or dolt.
From chowder (thick soup) plus head, combining two terms of insult. The metaphor compares a foolish person's brain to chowder—thick, lumpy, and not functioning properly. Popular in American slang from the 19th century.
Calling someone a chowderhead is pure regional American insult—it only makes sense if you're from New England where everyone knows what chowder is, making it one of the most geographically specific and deliciously absurd insults in English!
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