humaneness vs mercy

humaneness and mercy both are nouns.

Word	Noun	Adjective	Verb	Adverb
humaneness	Yes	No	No	No
mercy	Yes	No	No	No

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

humaneness: the quality of compassion or consideration for others (people or animals)
mercy: a disposition to be kind and forgiving

Other hyponyms of humaneness include humanity, mercifulness.

humaneness (noun)	mercy (noun)
the quality of compassion or consideration for others (people or animals)	leniency and compassion shown toward offenders by a person or agency charged with administering justice
	alleviation of distress; showing great kindness toward the distressed
	a disposition to be kind and forgiving
	the feeling that motivates compassion
	something for which to be thankful