A slang term for a female between the ages of 18 - 28; more specifically a college female that has slutty and dishonest tendencies. It is generally believed that this term is derived from the Old Testament story between the association of Eve and the Serpent in the Garden of Eden. Males can alert fellow males of the presence of a serpent by hissing to eachother.
We should hit up that party, Bobby said there will be a lot of freshman serpents there.
Stephanie is the exemplary serpent.