blue pimpernel vs mad-dog weed

blue pimpernel and mad-dog weed both are nouns.

Word	Noun	Adjective	Verb	Adverb
blue pimpernel	Yes	No	No	No
mad-dog weed	Yes	No	No	No

As nouns, blue pimpernel and mad-dog weed are synonyms defined as:

blue pimpernel and mad-dog weed: an American mint that yields a resinous exudate used especially formerly as an antispasmodic

Other synonyms of blue pimpernel include blue skullcap, mad-dog skullcap, Scutellaria lateriflora.

blue pimpernel (noun)	mad-dog weed (noun)
an American mint that yields a resinous exudate used especially formerly as an antispasmodic	an American mint that yields a resinous exudate used especially formerly as an antispasmodic