clammy locust vs locust tree

clammy locust and locust tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
clammy locust	Yes	No	No	No
locust tree	Yes	No	No	No

As nouns, locust tree is a hypernym of clammy locust; that is, locust tree is a word with a broader meaning than clammy locust:

clammy locust: small rough-barked locust of southeastern United States having racemes of pink flowers and glutinous branches and seeds
locust tree: any of various hardwood trees of the family Leguminosae

Other hypernyms of clammy locust include locust.

clammy locust (noun)	locust tree (noun)
small rough-barked locust of southeastern United States having racemes of pink flowers and glutinous branches and seeds	any of various hardwood trees of the family Leguminosae