Holy Writ vs Good Book

Holy Writ and Good Book both are nouns.

Word	Noun	Adjective	Verb	Adverb
Holy Writ	Yes	No	No	No
Good Book	Yes	No	No	No

As nouns, Holy Writ and Good Book are synonyms defined as:

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

Holy Writ (noun)	Good Book (noun)
the sacred writings of the Christian religions	the sacred writings of the Christian religions