ack-ack vs pom-pom

ack-ack and pom-pom both are nouns.

Word	Noun	Adjective	Verb	Adverb
ack-ack	Yes	No	No	No
pom-pom	Yes	No	No	No

As nouns, ack-ack and pom-pom are synonyms defined as:

Other synonyms of ack-ack include ack-ack gun, antiaircraft, antiaircraft gun, flack, flak.

ack-ack (noun)	pom-pom (noun)
artillery designed to shoot upward at airplanes	artillery designed to shoot upward at airplanes
	decoration consisting of a ball of tufted wool or silk; usually worn on a hat