15 possible answers to
Answers with 3 characters: BUG FAN NUT Answers with 4 characters: BUFF Answers with 5 characters: FIEND FREAK LOVER RAVER Answers with 6 characters: ZEALOT Answers with 7 characters: BOOSTER DEVOTEE FANATIC FANCIER Answers with 10 characters: AFICIONADO Answers with 11 characters: EAGERBEAVER