(n.) An older student of Oxford University who is known for preying on younger students, especially freshers, to fulfill his or her various sexual needs.
(v.) To shark: To attempt to pick up a younger student
(v.) To get sharked: To be picked up by an older student
Student one: Hey did you see Amy last night?
Student two: Yeah. What a shark! I saw her try to pick up three different younger guys.
Student one: Well, knowing her, I'm sure at least one of them got sharked.