Someone who is currently not dating, who wants to date, but has not attempted to start dating for a long time because they gave up, believe nobody is suitable, or is mentally exhausted from unsuccessful attempts.
Person 1: Hey man, you haven't dated in a while, why don't you go out and find someone.
Person 2: Can't, finding someone is a lost cause
Person 1: Ah, I get it, you're a discouraged dater