Synonyms and related words :
addict, bug, collector, craze, demon, eager beaver, energumen, enthusiast, fad, faddiness, faddishness, faddism, fanatic, fiend, freak, great one for, hobbyist, hound, infatuate, novelty, nut, pursuer, rage, rhapsodist, sucker for, visionary, wrinkle, zealot