pupil vs crammer

pupil and crammer both are nouns.

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

As nouns, crammer is a hyponym of pupil; that is, crammer is a word with a more specific, narrower meaning than pupil:

pupil (noun)	crammer (noun)
the contractile aperture in the center of the iris of the eye; resembles a large black dot	a textbook designed for cramming
a learner who is enrolled in an educational institution	a special school where students are crammed
a young person attending school (up through senior high school)	a student who crams
	a teacher who is paid to cram students for examinations