bone vs hit the books

bone is a noun but hit the books is not a noun.

Word	Noun	Adjective	Verb	Adverb
bone	Yes	Yes	Yes	No
hit the books	No	No	Yes	No

As verbs, hit the books is a hypernym of bone; that is, hit the books is a word with a broader meaning than bone:

Other hypernyms of bone include study.

bone (noun)	hit the books (noun)
a shade of white the color of bleached bones
rigid connective tissue that makes up the skeleton of vertebrates
the porous calcified substance from which bones are made

bone (adjective)	hit the books (adjective)
consisting of or made up of bone

bone (verb)	hit the books (verb)
remove the bones from	learn by reading books
study intensively, as before an exam