Added 9 October 2026 knucklehead /ˈnʌkl̩ˌhɛd/ noun Categories: PeopleObscure Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about knucklehead at Wordnik → Where our words come from → A stupid person; these words are used to express a low opinion of someone's intelligence. Related Words: duncelunkheadnumskullloggerheadblockheaddunderheadboneheadmuttonheadshitheadhammerheadlamebrainmoron Back to today's word