Noun
One who guesses; one who forms or gives an opinion without means of knowing.
Source: Webster's dictionaryThe public is a bad guesser. Thomas De Quincey
I shall always consider the best guesser the best prophet. Cicero
However, the guesser can also win by guessing all the letters or numbers that appears in the word, thereby completing the word, before the diagram is completed. Source: Internet
Otherwise, the other player may choose to penalize the guesser by adding an element to the diagram. Source: Internet
Estabrooks acted as the sender with the guesser in an adjoining room. Source: Internet
On the other hand, if the other player makes enough incorrect guesses to allow his opponent to complete the diagram, the game is also over, this time with the guesser losing. Source: Internet