fixity vs fixedness

fixity and fixedness both are nouns.

Word	Noun	Adjective	Verb	Adverb
fixity	Yes	No	No	No
fixedness	Yes	No	No	No

As nouns, fixity and fixedness are synonyms defined as:

fixity and fixedness: the quality of being fixed in place as by some firm attachment

Other synonyms of fixity include fastness, fixture, secureness.

fixity (noun)	fixedness (noun)
the quality of being fixed in place as by some firm attachment	the quality of being fixed in place as by some firm attachment
the quality of being incapable of mutation	the quality of being fixed and unchangeable
	remaining in place