Good Book vs Bible

Good Book and Bible both are nouns.

Word	Noun	Adjective	Verb	Adverb
Good Book	Yes	No	No	No
Bible	Yes	No	No	No

As nouns, Good Book and Bible are synonyms defined as:

Other synonyms of Good Book include Book, Christian Bible, Holy Scripture, Holy Writ, Scripture, Word, Word of God.

Good Book (noun)	Bible (noun)
the sacred writings of the Christian religions	the sacred writings of the Christian religions