republication vs republishing

republication and republishing both are nouns.

Word	Noun	Adjective	Verb	Adverb
republication	Yes	No	No	No
republishing	Yes	No	No	No

As nouns, republication and republishing are synonyms defined as:

republication (noun)	republishing (noun)
the act of publishing again	the act of publishing again
something that has been published again; a fresh publication (as of a literary work)