Synonyms and related words :
Boeotian, asinine, balky, beef-brained, beef-witted, blockish, bovine, bullheaded, cantankerous, chumpish, cloddish, contrary, cowish, crass, cross-grained, dense, difficult, doltish, dullard, dumb, duncical, duncish, fat, froward, gross, headstrong, ineducable, irascible, klutzy, lumpish, mulish, oafish, opaque, ornery, perverse, pigheaded, restive, self-willed, sottish, stiff-necked, stubborn, stuffy, stupid, sulky, sullen, thick, unteachable, wayward