flak vs fuse indicator regulator

flak and fuse indicator regulator both are nouns.

Word	Noun	Adjective	Verb	Adverb
flak	Yes	No	No	No
fuse indicator regulator	Yes	No	No	No

flak (noun)	fuse indicator regulator (noun)
artillery designed to shoot upward at airplanes	an instrument which sets the fuze time on projectiles with mechanical time fuzes.
intense adverse criticism
a slick spokesperson who can turn any criticism to the advantage of their employer