adjective

lacking good sense or judgement; unwise.

he was foolish enough to confide in her

stupid,silly,idiotic,half-witted,witless,brainless,mindless,thoughtless,imprudent,incautious,irresponsible,injudicious,indiscreet,unwise,unintelligent,unreasonable,ill-advised,ill-considered,impolitic,rash,reckless,foolhardy,lunatic,absurd,senseless,pointless,nonsensical,inane,fatuous,ridiculous,laughable,risible,derisible,dumb,dim,dim-witted,dopey,damfool,half-baked,hare-brained,crackbrained,pea-brained,wooden-headed,thickheaded,nutty,mad,crazy,dippy,cuckoo,screwy,wacky,barmy,daft,dotty,batty,gormless,glaikit,dumb-ass,chowderheaded,dotish