fixing vs fastener

fixing and fastener both are nouns.

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

As nouns, fixing and fastener are synonyms defined as:

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

Other synonyms of fixing include fastening, holdfast.

fixing (noun)	fastener (noun)
the act of putting something in working order again	restraint that attaches to something or holds something in place
the sterilization of an animal	a person who fastens or makes fast
(histology) the preservation and hardening of a tissue sample to retain as nearly as possible the same relations they had in the living body
restraint that attaches to something or holds something in place