fastener vs fastening

fastener and fastening both are nouns.

Word	Noun	Adjective	Verb	Adverb
fastener	Yes	No	No	No
fastening	Yes	No	No	No

As nouns, fastener and fastening are synonyms defined as:

fastener and fastening: restraint that attaches to something or holds something in place

Other synonyms of fastener include fixing, holdfast.

fastener (noun)	fastening (noun)
restraint that attaches to something or holds something in place	the act of fastening things together
a person who fastens or makes fast	restraint that attaches to something or holds something in place