halfwit
airhead (slang) berk (Brit. slang) charlie (Brit. informal) coot, dickhead (slang) dickwit (slang) dimwit (informal) dipstick (Brit. slang) divvy (Brit. slang) dolt, dork (slang) dullard, dunce, dunderhead, dweeb (U.S. slang) fathead (informal) fool, fuckwit (taboo slang) geek (slang) gobshite (Irish taboo slang) gonzo (slang) idiot, imbecile (informal) jerk (slang, chiefly U.S. & Canad.) lamebrain (informal) mental defective, moron, nerd or nurd (slang) nitwit (informal) numbskull or numskull, numpty (Scot. informal) oaf, pillock (Brit. slang) plank (Brit. slang) plonker (slang) prat (slang) prick (slang) schmuck (U.S. slang) simpleton, twit (informal, chiefly Brit.) wally (slang)