Meaning of "guess" in Essential American English Dictionary

guess

verb us /ɡes/

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.”

(Definition of “guess verb” from the Webster's Essential Mini Dictionary © Cambridge University Press)