mercy vs compassionateness

mercy and compassionateness both are nouns.

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

As nouns, compassionateness is a hypernym of mercy; that is, compassionateness is a word with a broader meaning than mercy:

Other hypernyms of mercy include compassion.

mercy (noun)	compassionateness (noun)
leniency and compassion shown toward offenders by a person or agency charged with administering justice	a deep awareness of and sympathy for another's suffering
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