Synonyms and related words :
alien, case, character, crackpot, crank, eccentric, fanatic, hermit, hobo, kook, lone wolf, loner, maverick, meshuggenah, natural, nonconformist, nut, odd fellow, oddball, oddity, original, outsider, pariah, queer fish, queer specimen, rara avis, screwball, solitary, tramp, type, zealot