A really sloppy, annoying, and usually slightly overweight sorority girl. She's most likely the black sheep of the group. This girl will be the most drunk, the most forward, and the most not attractive.

Woman so ugly you wouldn't touch her with a barge pole strapped to the end of a pole vault pole.

An ugly or disgusting girl

Although it is typically used as a noun, ie "she's a swampdonkey" (referring to a particularly nasty female) it can also be used as an exclamation of immunity. If a male and his peers go to a social function, one male from the group is allowed to claim "swampdonkey". This allows said male to take home even the dirtiest of barflies home with him while his mates are not allowed to give him a hard time of any kind. This is typically used when a male is on an extended dry spell.

A female meth addict.One who offers sex in exchange for oatmeal or cereal.

Descriptive for less than average looking bird when out on the pull.

someone who is seriously ugly and needs urgent plastic surgery if dey r gonna gat anywhere in life without people sayin "urrgh u r a minger/swampdonkey"