increment vs widening

increment and widening both are nouns.

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

As nouns, widening is a hyponym of increment; that is, widening is a word with a more specific, narrower meaning than increment:

increment: a process of becoming larger or longer or more numerous or more important
widening: an increase in width

increment (noun)	widening (noun)
the amount by which something increases	the act of making something wider
a process of becoming larger or longer or more numerous or more important	a part of a road that has been widened to allow cars to pass or park
	an increase in width