milk vetch vs milk-vetch

milk vetch and milk-vetch both are nouns.

Word	Noun	Adjective	Verb	Adverb
milk vetch	Yes	No	No	No
milk-vetch	Yes	No	No	No

As nouns, milk vetch and milk-vetch are synonyms defined as:

milk vetch and milk-vetch: any of various plants of the genus Astragalus

milk vetch (noun)	milk-vetch (noun)
any of various plants of the genus Astragalus	any of various plants of the genus Astragalus