second-guesser
nounUK /ˌsekəndˈɡesə/
US /ˌsekəndˈɡesər/
A person who keeps doubting or questioning choices that were already made.
My brother is such a second-guesser that he changed his dinner order three times.
RELATED WORDS
OTHER MEANINGS
2. Someone who predicts or guesses what will happen before it does.
As a second-guesser of election results, she was rarely wrong.
3. A person who criticizes decisions after the outcome is known.
The coach ignored the second-guessers who complained after the loss.
4. Someone who constantly rethinks their own actions and choices.
Being a second-guesser made it hard for him to ever feel confident.