We found 24 dictionaries that define the word knucklehead:

General (21 matching dictionaries)

1. knucklehead: Longman Dictionary of Contemporary English
2. knucklehead: Merriam-Webster
3. knucklehead: Oxford Learner's Dictionaries
4. knucklehead: American Heritage Dictionary of the English Language
5. knucklehead: Collins English Dictionary
6. knucklehead: Vocabulary.com
7. Knucklehead, knucklehead: Wordnik
8. knucklehead: Cambridge Advanced Learner's Dictionary
9. knucklehead: Wiktionary
10. knucklehead: Webster's New World College Dictionary, 4th Ed.
11. knucklehead: The Wordsmyth English Dictionary-Thesaurus
12. knucklehead: Infoplease Dictionary
13. knucklehead: Dictionary.com
14. Knucklehead (band), Knucklehead: Wikipedia, the Free Encyclopedia
15. knucklehead: Rhymezone
16. knucklehead: FreeDictionary.org
17. knucklehead: Mnemonic Dictionary
18. Knucklehead: The Word Detective
19. knucklehead: TheFreeDictionary.com

Computing (1 matching dictionary)

20. knucklehead: Encyclopedia

Slang (1 matching dictionary)

21. knucklehead: Green’s Dictionary of Slang

Tech (1 matching dictionary)

22. AUTOMOTIVE TERMS (No longer online)

(Note: See knuckleheaded as well.)

Definitions from Wiktionary ( ) ▸ noun:  (slang, derogatory) An idiot; a stupid or inept person. Similar: blockhead, dunderhead, loggerhead, muttonhead, lunkhead, dunce, bonehead, shithead, numskull, hammerhead, more... Opposite: genius, brainiac, prodigy, smartypants Types: dunce, idiot, moron, imbecile, dummy, dolt, dope, dumbass, more... Phrases: Harley-Davidson Knucklehead engine, more... Adjectives: little, such, inner, real, dutch, complete, old, big ▸ Words similar to knucklehead ▸ Usage examples for knucklehead ▸ Idioms related to knucklehead ▸ Wikipedia articles (New!) ▸ Popular adjectives describing knucklehead ▸ Words that often appear near knucklehead ▸ Rhymes of knucklehead ▸ Invented words related to knucklehead