Synonyms and related words :
absurd, apish, asinine, balmy, bananas, barmy, bats, batty, beany, bedlamite, befooled, beguiled, besotted, bonkers, brainless, buffoonish, buggy, bughouse, bugs, cockeyed, crackers, crazy, credulous, cuckoo, daffy, daft, dazed, dement, dippy, dizzy, doting, dotty, dumb, fatuitous, fatuous, flaky, flipped, fond, fool, foolheaded, foolish, freaked-out, fruitcakey, fruity, fuddled, futile, gaga, goofy, gulled, harebrained, haywire, idiotic, imbecile, inane, inept, infatuated, insane, just plain nuts, kooky, loon, loopy, mad, madman, maniac, maudlin, moronic, non compos, nut, nuts, nutty, off the hinges, off the track, off the wall, potty, preposterous, round the bend, sappy, screwball, screwballs, screwy, senseless, sentimental, silly, slaphappy, stupid, thoughtless, wacky, wet, witless