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.
1.
When that drunken fat chick at the footy wouldn't shut the fuck up! Leon had no choice but to call her a Slughorn.

2.
" You have too slay a few Slughorns to get to the Princess."
by Benndoggy June 23, 2012
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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.
1. Ugh. He's only in that goddamned frat so he can be more of a Slughorn.

2. That fucking Slughorn just made friends with the Art Teacher because he's going to that Arts Festival.

3. What a Slughorn. (In response to a friend throwing his phone number at a band member at a concert)
by RadioactivePuppy December 6, 2010
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