textbook vs crammer

textbook and crammer both are nouns.

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

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

Other hyponyms of textbook include introduction, primer, reader.

textbook (noun)	crammer (noun)
a book prepared for use in schools or colleges	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

textbook (adjective)	crammer (adjective)
according to or characteristic of a casebook or textbook; typical