firing vs sacking

firing and sacking both are nouns.

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

As nouns, firing and sacking are synonyms defined as:

firing and sacking: the termination of someone's employment (leaving them free to depart)

Other synonyms of firing include discharge, dismissal, dismission, liberation, release, sack.

firing (noun)	sacking (noun)
the act of setting something on fire	the termination of someone's employment (leaving them free to depart)
the termination of someone's employment (leaving them free to depart)	coarse fabric used for bags or sacks
the act of discharging a gun
the act of firing weapons or artillery at an enemy