Synonyms and related words :
Boeotian, absurd, airy, apish, batty, beef-brained, beef-witted, befooled, beguiled, besotted, blockish, bovid, bovine, brainless, buffoonish, caprid, caprine, catchpenny, chumpish, cloddish, cockeyed, cowish, cowlike, crass, crazy, credulous, daffy, daft, dazed, deerlike, dense, dizzy, doltish, doting, dullard, dumb, duncical, duncish, empty, equestrian, equine, fat, fatuitous, fatuous, flaky, flimsy, fond, fool, foolheaded, foolish, fribble, fribbling, frivolous, frothy, fuddled, futile, gaga, goatish, goatlike, goofy, gross, gulled, hircine, hoggish, hoofed, horsy, idiotic, idle, imbecile, inane, ineducable, inept, infatuated, insane, irrational, klutzy, kooky, light, loony, lumpish, mad, maudlin, mindless, moronic, mulish, nugacious, nugatory, nutty, oafish, opaque, otiose, ovine, piggish, puerile, ruminant, sappy, screwy, senseless, sentimental, shallow, sheepish, sheeplike, silly, slender, slight, sottish, stupid, superficial, swinish, thick, thoughtless, trifling, trite, trivial, ungulate, unreasonable, unteachable, unwitty, vacuous, vain, vapid, wacky, weak-minded, wet, windy, witless, wrongheaded