0 past simple and past participle of guess
1 to give an answer to a particular question when you do not have all the facts and so cannot be certain if you are correct:
[ + question word ] Guess when this was built.
[ + (that) ] I guessed (that) she was your sister.
[ + question word ] I bet you can't guess how old he is.
"You have a new job, don't you?" "Yes, how did you guess?"
[ + (that) ] I guess (that) things are pretty hard for you now.
I'm never going to guess the answer if you don't give me a clue.
She presents such a cheerful front that you'd never guess she's ill.
From her slow, deliberate speech I guessed she must be drunk.
No prizes for guessing where Daniel is.
She gave the present a quick squeeze and tried to guess what was inside.
Virtually almost every word which can be guessed by the morphological rules is guessed exactly correct (97% recall and 97% precision).
He saw that implicit contracts had something to say about that and guessed that the two of us might make interesting colleagues.
The listeners accurately guessed the self-identified sexuality of the speakers 79.6% of the time.