direct fire vs firing

direct fire and firing both are nouns.

Word	Noun	Adjective	Verb	Adverb
direct fire	Yes	No	No	No
firing	Yes	No	No	No

As nouns, firing is a hypernym of direct fire; that is, firing is a word with a broader meaning than direct fire:

direct fire: fire delivered on a target that is visible to the person aiming it
firing: the act of firing weapons or artillery at an enemy

Other hypernyms of direct fire include fire.

direct fire (noun)	firing (noun)
fire delivered on a target that is visible to the person aiming it	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