shit-for-brains /ˈʃɪt fɚ ˌbɹeɪnz/adjective 1noun 2 adjective1 •(vulgar, offensive) Extremely stupid.That shit-for-brains neighbor of mine is shooting off amateur fireworks again. noun2 •(vulgar, offensive) An unintelligent, foolish person; an idiot. •(vulgar, offensive) An extremely stupid person.That new assistant of yours is a real shit-for-brains.He's another one of those shit-for-brains.