verb

 

say without knowing to give an answer or opinion about something without having all the facts

Can you guess how old he is?

 

say correctly without knowing to give a correct answer without having all the facts

"You've got a promotion!" "Yes, how did you guess?"

 

noun

 

attempt an attempt to give the right answer when you are not certain what it is

How old do you think John is? Go on, UK have a guess/US take a guess.

 

opinion an opinion that you have formed by guessing

My guess is they'll announce their engagement soon.