Synonyms and related words :
Pickwickian, absurd, airy, apish, arch, asinine, batty, befooled, beguiled, bemused, besotted, beyond belief, bizarre, blockheaded, boneheaded, brainless, brash, buffoonish, catchpenny, cockamamie, cockeyed, confused, crazy, credulous, cuckoo, daffy, daft, dazed, demented, devilish, dim, dim-witted, dippy, dizzy, dopey, doting, dotty, dull-witted, dumb, elfish, elvish, empty, empty-headed, erratic, extravagant, fantastic, fatuitous, fatuous, feebleminded, flaky, flimsy, fond, fool, foolhardy, foolheaded, fribble, fribbling, frivolous, frothy, fuddled, full of mischief, futile, gaga, goofy, grotesque, gulled, hasty, headless, headlong, heedless, high-flown, high-spirited, idiotic, idle, ignorant, ill-advised, ill-considered, illogical, imbecile, imbecilic, impetuous, impish, impolitic, imprudent, inane, incautious, incredible, indiscreet, inept, infatuated, injudicious, insane, insensate, irrational, knavish, kooky, lackbrained, laughable, lean-minded, lean-witted, light, light-headed, loony, ludicrous, mad, maudlin, mindless, mischief-loving, mischievous, misguided, monstrous, moronic, nonsensical, not bright, nugacious, nugatory, numskulled, nuts, nutty, obtuse, of little brain, otiose, outrageous, outre, pea-brained, pin-brained, playful, poppycockish, potty, prankish, pranksome, pranky, preposterous, puckish, rash, reasonless, reckless, ridiculous, roguish, rubbishy, sappy, scampish, scapegrace, scatterbrained, screwy, senseless, sentimental, shallow, short-sighted, silly, skimble-skamble, slackminded, slackwitted, slender, slight, slow-witted, sportive, stolid, stupid, superficial, thick, thickheaded, thoughtless, trashy, trickish, tricksy, trifling, trite, trivial, twaddling, twaddly, ungifted, unintellectual, unintelligent, unorthodox, unreasonable, unreasoning, unstable, untalented, unthinking, unwary, unwise, unwitty, vacuous, vain, vapid, wacky, waggish, weak-minded, weird, wet, wild, windy, witless