guess 
(gĕs)
(gĕs)v. guessed, guess·ing, guess·es
v.tr.
1.
a. To predict (a result or an event) without sufficient information.
b. To assume, presume, or assert (a fact) without sufficient information.
2. To form a correct estimate or conjecture of: guessed the answer.
3. To suppose; think: I guess he was wrong.
v.intr.
1. To make an estimate or conjecture: We could only guess at her motives.
2. To estimate or conjecture correctly.
n.
1. An act or instance of guessing.
2. A conjecture arrived at by guessing.
[Middle English gessen, probably of Scandinavian origin; see ghend- in the Appendix of Indo-European roots.]
guesser n.