circular vs cyclic

circular is a noun but cyclic is not a noun.

Word	Noun	Adjective	Verb	Adverb
circular	Yes	Yes	No	No
cyclic	No	Yes	No	No

circular (noun)	cyclic (noun)
an advertisement (usually printed on a page or in a leaflet) intended for wide distribution

circular (adjective)	cyclic (adjective)
having the shape or form of a circle	recurring in cycles
describing a circle; moving in a circle	of a compound having atoms arranged in a ring structure
	forming a whorl or having parts arranged in a whorl
	conforming to the Carnot cycle
	marked by repeated cycles