Guess (verb)

1. To form an opinion or conclusion about (something) based on limited information.
2. To make a conjecture or estimate about a quantity, time, or value.
3. To presume or assume something to be true without definite proof.

Origin:

Middle english gessen, from old norse gissa; related to old high german gissōn to guess.

Examples:

1. I guess the flight will arrive on time.
2. Can you guess how many candies are in the jar?
3. She guessed that the test would be hard.
4. I'm just guessing, but I think it's going to rain today.
5. He guessed the password with three tries.