adjective

(of a person or their behaviour) unconventional and slightly strange.

he noted her eccentric appearance

unconventional,uncommon,abnormal,irregular,aberrant,anomalous,odd,queer,strange,peculiar,weird,bizarre,off-centre,outlandish,freakish,extraordinary,idiosyncratic,quirky,singular,nonconformist,capricious,whimsical,outré,avant garde,way out,far out,offbeat,nutty,screwy,freaky,oddball,wacky,cranky,off the wall,madcap,zany,rum,dotty,kooky,wacko,bizarro,in left field

noun

a person of unconventional and slightly strange views or behaviour.

he’s seen as a local eccentric

oddity,odd fellow,unorthodox person,character,individualist,individual,free spirit,misfit,oddball,weirdo,weirdie,freak,nut,nutcase,case,head case,crank,crackpot,loony,loon,one-off,odd bod,nutter,queer fish,wacko,wack,screwball,kook,wackadoo,wackadoodle,dingbat