Describes an individual so flawed that they cannot possibly be dated by anyone.
Mandy: Phil is so completely undateable. I have no idea why my cousin set us up.
Tamara: What happened?!?
Mandy: For starters, he is 35 and lives with his parents, and he smelled like rotten vegetation. And there were nose hairs.
Tamara: Agreed. Undateable.