Pickwickian, absurd, airy, apish, asinine, balmy, batty, bedazzled, befooled, beguiled, benumbed, besotted, blockhead, bonehead, booby, brainless, buffoonish, catchpenny, childish, clod, clot, cockeyed, crazy, credulous, daffy, daft, daze, dazed, dazzled, dippy, dizzy, dolt, dope, dopey, doting, drip, dumb, dummy, dunce, empty-headed, empty, fatuitous, fatuous, featherbrained, flaky, flighty, flimsy, fond, fool, foolhardy, foolheaded, foolish, fribble, fribbling, frivolous, frothy, fuddled, futile, gaga, giddy, goofy, goose, groggy, gulled, harebrained, idiot, idiotic, idle, ignoramus, ignorant, illogical, imbecile, imbecilic, in a daze, inane, inept, infatuated, insane, irrational, irresponsible, jackass, jerk, knocked silly, kooky, laughable, light-headed, light, loony, ludicrous, mad, maudlin, mazed, moronic, muzzy, nerd, nincompoop, ninny, nitwit, nitwitted, nonsensical, nugacious, nugatory, numskull, nutty, off, otiose, pointless, poppycockish, preposterous, puerile, punch-drunk, punchy, rattlebrained, ridiculous, risible, rubbishy, sappy, scatterbrained, screwy, senseless, sentimental, shallow, silly Billy, silly ass, simpleton, skimble-skamble, slaphappy, slender, slight, stunned, stupefied, stupid, superficial, thoughtless, trashy, trifling, trite, trivial, twaddling, twaddly, twit, unintelligent, unreasonable, unwise, unwitty, vacuous, vain, vapid, wacky, weak-minded, wet, windy, witless, woozy