unsupported vs strapless

unsupported is not a noun while strapless is a noun.

Word	Noun	Adjective	Verb	Adverb
unsupported	No	Yes	No	No
strapless	Yes	Yes	No	No

unsupported (noun)	strapless (noun)
	a woman's garment that exposes the shoulders and has no shoulder straps

unsupported (adjective)	strapless (adjective)
not held up or borne	having no straps
not sustained or maintained by nonmaterial aid