From Middle English gessere, gessare, equivalent to guess + -er.
guesser (plural guessers)
- A person who guesses; especially someone who can make a reasonable prediction from little evidence.
1934, Agatha Christie, chapter 8, in Murder on the Orient Express, London: HarperCollins, published 2017, page 255:
'Then, believe me, you're a pretty slick guesser.'