gradualness vs gentleness

gradualness and gentleness both are nouns.

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

As nouns, gradualness and gentleness are synonyms defined as:

gradualness and gentleness: the property possessed by a slope that is very gradual

gradualness (noun)	gentleness (noun)
the quality of being gradual or of coming about by gradual stages	acting in a manner that is gentle and mild and even-tempered
the property possessed by a slope that is very gradual	the property possessed by a slope that is very gradual