cram vs crammer

cram is not a noun while crammer is a noun.

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

cram (noun)	crammer (noun)
	a textbook designed for cramming
	a special school where students are crammed
	a student who crams
	a teacher who is paid to cram students for examinations

cram (verb)	crammer (verb)
prepare (students) hastily for an impending exam
study intensively, as before an exam
crowd or pack to capacity
put something somewhere so that the space is completely filled