Slughorn

[Luis Fok]

N. The person who hoards friends whom they find beneficial or make them feel special. Usually a total fucking loser or a person with underdeveloped social skills who believes obtaining more friends to add to their collection makes them a better person. A play on Horace Slughorn, the Defense Against the Dark Arts teacher who uses the status of his friends to judge his personal success. Loser.

[Zipporah Schumaker]

A Slughorn is pretty much an undesirable woman with a loud mouth. Whether she is fat, ugly or a straight up retard, she must be undesirable.
However, in some circumstances a desirable woman may be called a slughorn. For example during times of drunken frustration or when she has just pissed you off.