unusual vs singular

unusual is not a noun while singular is a noun.

Word	Noun	Adjective	Verb	Adverb
unusual	No	Yes	No	No
singular	Yes	Yes	No	No

unusual (noun)	singular (noun)
	the form of a word that is used to denote a singleton

unusual (adjective)	singular (adjective)
not usual or common or ordinary	grammatical number category referring to a single item or unit
being definitely out of the ordinary and unexpected; slightly odd or even a bit weird	composed of one member, set, or kind
not commonly encountered	unusual or striking
	being a single and separate person or thing
	the single one of its kind
	beyond or deviating from the usual or expected