hesitator

/ˈhɛzɪteɪtər/
noun
  1. A person who hesitates or is slow to make decisions.
    • The team needed a decisive leader, not a hesitator who second-guessed every move.
    • As a natural hesitator, she often missed out on good opportunities.
    • The coach told the hesitator on the field to trust his instincts and act quickly.
Antonyms