zealot

/ˈzɛlət/
noun
  1. A person who is extremely enthusiastic and passionate about a particular belief, cause, or activity, often to an excessive or fanatical degree.
    • She was a fitness zealot who went to the gym twice a day, rain or shine.
    • The art critic dismissed the painter's followers as zealots who refused to see any flaws in his work.
    • The political zealot spent every weekend campaigning for his candidate.
Antonyms
What does "zealot" mean? | whatsthatwordmean | whatsthatwordmean