guard of honor vs honor guard

guard of honor and honor guard both are nouns.

Word	Noun	Adjective	Verb	Adverb
guard of honor	Yes	No	No	No
honor guard	Yes	No	No	No

As nouns, guard of honor and honor guard are synonyms defined as:

guard of honor and honor guard: an escort for a distinguished guest or for the casket at a military funeral

guard of honor (noun)	honor guard (noun)
an escort for a distinguished guest or for the casket at a military funeral	an escort for a distinguished guest or for the casket at a military funeral