A "negative student"? I've been a college teacher for years and never heard of a student being characterized as either positive or negative. Some are A+. Some may fail. But "negative"?
Does this mean the student is doing badly, failing the course? Or is it talking about the students attitude?
There are many negative students in Duolingo too. See comments around. Disfory. Dysthymy. Anhedony. Melancholy. Subdepression. Etc.
Pupil is actually more correct, since סטודנט is used for college student, and תלמיד refers to a primary or secondary school pupil. In the US, the term 'student' is now applied to all levels of education.