fixing vs darning

fixing and darning both are nouns.

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

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

fixing (noun)	darning (noun)
the act of putting something in working order again	the act of mending a hole in a garment with crossing threads
the sterilization of an animal
(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