black archangel vs fetid horehound

black archangel and fetid horehound both are nouns.

Word	Noun	Adjective	Verb	Adverb
black archangel	Yes	No	No	No
fetid horehound	Yes	No	No	No

As nouns, black archangel and fetid horehound are synonyms defined as:

black archangel and fetid horehound: ill-smelling European herb with rugose leaves and whorls of dark purple flowers

Other synonyms of black archangel include Ballota nigra, black horehound, stinking horehound.

black archangel (noun)	fetid horehound (noun)
ill-smelling European herb with rugose leaves and whorls of dark purple flowers	ill-smelling European herb with rugose leaves and whorls of dark purple flowers