trojan horse vs trojan

trojan horse and trojan both are nouns.

Word	Noun	Adjective	Verb	Adverb
trojan horse	Yes	No	No	No
trojan	Yes	No	No	No

As nouns, trojan horse and trojan are synonyms defined as:

trojan horse and trojan: a program that appears desirable but actually contains something harmful

trojan horse (noun)	trojan (noun)
a program that appears desirable but actually contains something harmful	a program that appears desirable but actually contains something harmful