swallow-tailed coat vs swallowtail

swallow-tailed coat and swallowtail both are nouns.

Word	Noun	Adjective	Verb	Adverb
swallow-tailed coat	Yes	No	No	No
swallowtail	Yes	No	No	No

As nouns, swallow-tailed coat and swallowtail are synonyms defined as:

swallow-tailed coat and swallowtail: a man's full-dress jacket with two long tapering tails at the back

Other synonyms of swallow-tailed coat include morning coat.

swallow-tailed coat (noun)	swallowtail (noun)
a man's full-dress jacket with two long tapering tails at the back	a man's full-dress jacket with two long tapering tails at the back