widening vs widen

widening is a noun but widen is not a noun.

Word	Noun	Adjective	Verb	Adverb
widening	Yes	No	No	No
widen	No	No	Yes	No

widening (noun)	widen (noun)
the act of making something wider
a part of a road that has been widened to allow cars to pass or park
an increase in width

widening (verb)	widen (verb)
	become broader or wider or more extensive
	extend in scope or range or area
	make wider
	make (clothes) larger