constraint vs fixing

constraint and fixing both are nouns.

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

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

constraint (noun)	fixing (noun)
the act of constraining; the threat or use of force to control the thoughts or behavior of others	the act of putting something in working order again
a device that retards something's motion	the sterilization of an animal
the state of being physically constrained	(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