A stupid or foolish person; someone who is silly or not intelligent.
From 'chuckle' (possibly meaning to laugh foolishly) plus 'head' (meaning a person), combining to suggest someone who acts silly or laughs at inappropriate things.
In old English insults, 'head' compounds were super common—'blockhead,' 'meathead,' 'bonehead'—because calling someone a foolish type of head was insulting without being too mean!
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