student vs pupil

student and pupil both are nouns.

Word	Noun	Adjective	Verb	Adverb
student	Yes	No	No	No
pupil	Yes	No	No	No

As nouns, student and pupil are synonyms defined as:

student and pupil: a learner who is enrolled in an educational institution

Other synonyms of student include educatee.

student (noun)	pupil (noun)
a learner who is enrolled in an educational institution	the contractile aperture in the center of the iris of the eye; resembles a large black dot
someone (especially a child) who learns (as from a teacher) or takes up knowledge or beliefs	a learner who is enrolled in an educational institution
	a young person attending school (up through senior high school)