black horehound vs black archangel

black horehound and black archangel both are nouns.

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

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

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

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

black horehound (noun)	black archangel (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