Merriam-Webster's Collegiate® Dictionary, 11th Edition
GUESS
I. verb see: get
Date: 14th century
transitive verb to form an opinion of from little or no evidence, believe , suppose , to arrive at a correct conclusion about by conjecture, chance, or intuition , intransitive verb to make a guess, guessable adjective guesser noun
II. noun
Date: 14th century
conjecture , surmise