comic book vs mag

comic book and mag both are nouns.

Word	Noun	Adjective	Verb	Adverb
comic book	Yes	No	No	No
mag	Yes	No	No	No

As nouns, mag is a hypernym of comic book; that is, mag is a word with a broader meaning than comic book:

comic book: a magazine devoted to comic strips
mag: a periodic publication containing pictures and stories and articles of interest to those who purchase it or subscribe to it

Other hypernyms of comic book include magazine.

comic book (noun)	mag (noun)
a magazine devoted to comic strips	a periodic publication containing pictures and stories and articles of interest to those who purchase it or subscribe to it