slope vs gradualness

slope and gradualness both are nouns.

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

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

slope: 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 slope include grade, pitch, rake, slant, abruptness, precipitousness, steepness, gentleness.

slope (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
an elevated geological formation	the property possessed by a slope that is very gradual

slope (verb)	gradualness (verb)
be at an angle