sceptic

/ˈskɛptɪk/
noun
  1. A person who questions or doubts claims, ideas, or beliefs that are often accepted by others.
    • The scientist remained a sceptic until she saw the data herself.
    • Even as a sceptic, he admitted the magic trick was impressive.
    • My friend is a sceptic and doesn't believe in conspiracy theories.
Antonyms
What does "sceptic" mean? | whatsthatwordmean | whatsthatwordmean