firing off vs firing

firing off and firing both are nouns.

Word	Noun	Adjective	Verb	Adverb
firing off	Yes	No	No	No
firing	Yes	No	No	No

As nouns, firing off and firing are synonyms defined as:

Other synonyms of firing off include discharge.

firing off (noun)	firing (noun)
the act of discharging a gun	the act of setting something on fire
	the termination of someone's employment (leaving them free to depart)
	the act of discharging a gun
	the act of firing weapons or artillery at an enemy