Originally Defined in How I Met Your Mother by Robin Scherbatsky and Marshall Eriksen --- a euphemism for stringing along someone's interest in you until someone better is available.
Dude 1: She said "I can't be with you..........Right now"
Dude 2: You're so hooked
Dude1: No I'm not!
Dude 2: That was a classic hooker line, and you are the hookee!
Dude 1: But But!
Dude 2 : No But, you're a hookee