college man vs pupil

college man and pupil both are nouns.

Word	Noun	Adjective	Verb	Adverb
college man	Yes	No	No	No
pupil	Yes	No	No	No

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

Other hypernyms of college man include educatee, student.

college man (noun)	pupil (noun)
a student (or former student) at a college or university	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)