gradualness vs fastness

gradualness and fastness both are nouns.

Word	Noun	Adjective	Verb	Adverb
gradualness	Yes	No	No	No
fastness	Yes	No	No	No

As nouns, fastness is a hypernym of gradualness; that is, fastness is a word with a broader meaning than gradualness:

gradualness: the quality of being gradual or of coming about by gradual stages
fastness: a rate (usually rapid) at which something happens

Other hypernyms of gradualness include speed, swiftness.

gradualness (noun)	fastness (noun)
the quality of being gradual or of coming about by gradual stages	a strongly fortified defensive structure
the property possessed by a slope that is very gradual	a rate (usually rapid) at which something happens
	the quality of being fixed in place as by some firm attachment