enthusiast (n.)
- activist
- addict
- adherent
- admirer
- aficionado
- bear
- beaver
- bigot
- booster
- buff
- bug
- bum
- champion
- collector
- crank
- daydreamer
- demon
- devotee
- disciple
- doer
- dreamer
- escapist
- extremist
- faddist
- fan
- fanatic
- fiend
- follower
- freak
- go-getter
- groupie
- habitue
- head
- hobbyist
- hound
- hustler
- idealist
- lotus-eater
- lover
- maniac
- militant
- monomaniac
- nut
- operator
- partisan
- powerhouse
- promoter
- prophet
- pursuer
- romancer
- romantic
- romanticist
- seer
- supporter
- utopian
- visionary
- votary
- winner
- zealot