a silly or stupid person; a person who lacks judgment or sense.

a professional jester, formerly kept by a person of royal or noble rank for amusement

the court fool.

a person who has been tricked or deceived into appearing or acting silly or stupid

to make a fool of someone.

an ardent enthusiast who cannot resist an opportunity to indulge an enthusiasm (usually prec. by a present participle)

He's just a dancing fool.

a weak-minded or idiotic person.

to trick, deceive, or impose on

They tried to fool him.

to act like a fool; joke; play.

to jest; pretend; make believe

I was only fooling.

fool around,

to putter aimlessly; waste time

She fooled around all through school.

to philander or flirt.

to be sexually promiscuous, esp. to engage in adultery.

fool away, to spend foolishly, as time or money; squander

to fool away the entire afternoon.

fool with, to handle or play with idly or carelessly

to be hurt while fooling with a loaded gun; to fool with someone's affections.

be nobody's fool

to be wise or shrewd.

noun

brain

noun

ass , birdbrain , blockhead * , bonehead * , boob * , bore , buffoon , clod * , clown , cretin * , dimwit * , dolt * , dope * , dumb ox , dunce , dunderhead , easy mark * , fair game , fathead , goose * , halfwit , idiot , ignoramus , illiterate , imbecile , innocent , jerk * , lamebrain * , lightweight * , loon , moron , nerd * , nincompoop * , ninny , nitwit , numskull * , oaf , sap * , schlemiel * , silly , simpleton , stooge * , sucker , turkey , twerp , twit , victim , jackass , mooncalf , nincompoop , simple , softhead , tomfool , butt , gull , lamb , pushover , addlepate , beetlehead , blatherskite , blockhead , blunderer , booby , clodpate , coot , cretin , defective , dolt , dotterel , driveler , droll , duffer , dullard , fop , harlequin , jester , merry-andrew , natural , numskull , scaramouch , schlemiel , wiseacre , witling , zany , zombie

verb

bamboozle * , bluff , cheat , chicane , con , deceive , delude , diddle , dupe , fake out , flimflam * , fox * , gull , hoax , hoodwink * , jive * , juke , kid , lead on , make believe , outfox , play-act , play a trick on , pretend , put on , put one over on , scam * , snow * , spoof * , suck in , take in * , trifle , beguile , betray , cozen , double-cross , hoodwink , humbug , mislead , take in , trick , doodle , putter , fiddle , meddle , mess , tinker , fidget , monkey , play , toy , twiddle , ass , bamboozle , blockhead , blunderer , bonehead , boob , buffoon , butt , chump , clown , comedian , coxcomb , cretin , cully , dawdle , dimwit , dolt , dope , dumbbell , dunce , dunderhead , fake , fathead , goose , idiot , imbecile , jerk , jest , joke , meathead , moron , nincompoop , ninny , nitwit , numskull , oaf , outwit , sap , scam , schlemiel , silly , simp , simpleton , spoof , stooge , sucker , tamper , tease , victim , victimize

phrasal verb

doodle , fool , putter , jest , pet* , spoon* , womanize , consume , dissipate , fritter away , riot away , squander , throw away , trifle away