Gunner

A Gunner is usually a very competitive person. Most uses are in the context of a highly competitive and sabotaging medical student.

For example, a medical student who claims he doesn't study and wants a non-competitive speciality like internal medicine while he is preparing for plastic surgery.

Basically, someone working hard in the background.

Hey, did you study that lecture? No? Don't listen to Mohammed again it is included in the final, he is such a Gunner!!