Other forms: second-guessing, second-guessed
To second-guess is to doubt a decision after making it. Stop second-guessing yourself, second-guess the referee, second-guessing every choice.
It also means to try to anticipate what somebody else will do, which is the older sense and comes from baseball. Second-guessing yourself is corrosive because it happens after the information that would have helped has arrived.
1verbsecond-guessTo doubt a decision after making it.
“Once you've handed in the exam, stop second-guessing your answers and try to relax.”
second-guess is a doubting.
A back-formation from second guesser, originally from baseball, recorded from about 1941.
A a back-formation from second guesser, originally from baseball. First use appears c. 1941.
Etymology from Wiktionary, CC BY-SA
Practised in Thinking & Memory