stupidSome people are too stupid to realize what's bad for them.
foolishShe was really foolish to quit her job like that.
sillyIt was silly of you to go out in the sun without a hat.
crazyYou'd be absolutely crazy to marry that man.
dumbmainlyUSinformalShe was terrified of asking dumb questions.
unintelligentThey are not unintelligent, just ill-informed.
absurdWhat an absurd thing to say!
ridiculousDo I look ridiculous in this hat?
ludicrousI think giving young children such expensive jewellery is a ludicrous idea.
out of your mindYou must be out of your mind spending so much money on a car.
ignorantSome ignorant person has parked across our drive.