Adj: A one-sided relationship that not only fails to ever get romantic, but that manages to get you publicly humiliated in front of your peers when the object of your affections openly dates someone else.
from: "platonic" and the demotion of Pluto to dwarf planet status.
student 1: Hey, WTF? Isn't that your girlfriend smooching with the captain of the football team?
student 2: Yes, Betty and I have a plutonic relationship. She respects my mind.
student 1: Sure, you sorry-ass loser!