fifth column vs Trojan horse

fifth column and Trojan horse both are nouns.

Word	Noun	Adjective	Verb	Adverb
fifth column	Yes	No	No	No
Trojan horse	Yes	No	No	No

As nouns, fifth column and Trojan horse are synonyms defined as:

fifth column and Trojan horse: a subversive group that supports the enemy and engages in espionage or sabotage; an enemy in your midst

fifth column (noun)	Trojan horse (noun)
a subversive group that supports the enemy and engages in espionage or sabotage; an enemy in your midst	a subversive group that supports the enemy and engages in espionage or sabotage; an enemy in your midst