gradient vs gradualness

gradient and gradualness both are nouns.

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

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

gradient: the property possessed by a line or surface that departs from the horizontal
gradualness: the property possessed by a slope that is very gradual

Other hyponyms of gradient include grade, pitch, rake, slant, abruptness, precipitousness, steepness, gentleness.

gradient (noun)	gradualness (noun)
the property possessed by a line or surface that departs from the horizontal	the quality of being gradual or of coming about by gradual stages
a graded change in the magnitude of some physical quantity or dimension	the property possessed by a slope that is very gradual