circumference vs circumferent

circumference is a noun but circumferent is not a noun.

Word	Noun	Adjective	Verb	Adverb
circumference	Yes	No	No	No
circumferent	No	Yes	No	No

circumference (noun)	circumferent (noun)
the size of something as given by the distance around it
the length of the closed curve of a circle
the boundary line encompassing an area or object

circumference (adjective)	circumferent (adjective)
	closely encircling