law student vs pupil

law student and pupil both are nouns.

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

As nouns, pupil is a hypernym of law student; that is, pupil is a word with a broader meaning than law student:

Other hypernyms of law student include educatee, student.

law student (noun)	pupil (noun)
a student in law school	the contractile aperture in the center of the iris of the eye; resembles a large black dot
	a learner who is enrolled in an educational institution
	a young person attending school (up through senior high school)