1. Obsession with one's marks;
2. Willingness to do anything for higher marks;
3. The philosophy a person who actually wants to do something useful in life;
4. something all serious students should be.
A: I could've totally gotten a 90! Why do I always get 89?
B: Stop complaining, why are you such a marksist?
A: A what?
B: Marksist! You're obsessed with your marks!
A: ... Oh. Well, I'm a senior, my marks are important!
B: That's true. I guess marksism is a must.