noun

a person who is slow at learning; a stupid person.

he was baffled by arithmetic and they called him a dunce at school

fool,idiot,stupid person,simpleton,halfwit,ignoramus,oaf,dolt,dullard,moron,imbecile,cretin,dummy,dumbo,dumb-bell,dum-dum,clot,thickhead,nitwit,dimwit,dope,duffer,booby,chump,numbskull,nincompoop,bonehead,blockhead,fathead,meathead,airhead,birdbrain,pea-brain,lamebrain,jerk,ninny,donkey,wally,numpty,berk,twerp,twonk,divvy,nit,mug,ass,pillock,wazzock,silly billy,doofus,goof,goofball,schmuck,putz,bozo,boob,dumbhead,dumbass,lamer,lummox,turkey,wing nut,galah,drongo,dingbat,knobhead,asshat