English definition of “guess”
A2 to give an answer or opinion about something without knowing all the facts: Guess how old he is.
A2 to say something that is right without knowing all the facts: How did you guess I was pregnant?
guess what? informal A2 used before telling someone something interesting or surprising: Guess what? We’re going to Hawaii!
I guess B1 used when you think something is probably true: I guess you’re mad at me.
I guess so/not › used when you agree or disagree but are not completely certain about something: “It would be better to buy a new car than to try to fix this one.” “Yeah, I guess so.”