leopard's-bane vs leopardbane

leopard's-bane and leopardbane both are nouns.

Word	Noun	Adjective	Verb	Adverb
leopard's-bane	Yes	No	No	No
leopardbane	Yes	No	No	No

As nouns, leopard's-bane and leopardbane are synonyms defined as:

leopard's-bane and leopardbane: any of several herbs of the genus Doronicum having alternate often clasping stem leaves cultivated for their long stalks of yellow flower heads

leopard's-bane (noun)	leopardbane (noun)
any of several herbs of the genus Doronicum having alternate often clasping stem leaves cultivated for their long stalks of yellow flower heads	any of several herbs of the genus Doronicum having alternate often clasping stem leaves cultivated for their long stalks of yellow flower heads