RhymeZone: meathead definitions

Definitions of meathead:

noun: (slang) An ungainly, dull or stupid person; someone who is lazy, disrespectful and/or whose beliefs and philosophies clash with another.
noun: (slang) A large, muscular, stupid man, especially an athlete.
noun: (military, slang, Canada) A member of the Canadian Forces Military Police.

(Definitions from Wiktionary)