Guesser (noun)

1. A person who guesses, especially habitually or professionally.
2. A person who is skilled at guessing.

Origin:

The word "guesser" comes from the verb "guess" which means "to form a conjecture or estimate about something without sufficient information to be sure of being correct.".

Examples:

1. He was a good guesser and often won the game.
2. The guesser had a knack for figuring out the answer.
3. She was a professional guesser and was paid to guess the answers.
4. The guesser was able to correctly guess the password.
5. The guesser had a 50/50 chance of guessing the right answer.