hardheartedness vs coldheartedness

hardheartedness and coldheartedness both are nouns.

Word	Noun	Adjective	Verb	Adverb
hardheartedness	Yes	No	No	No
coldheartedness	Yes	No	No	No

As nouns, hardheartedness and coldheartedness are synonyms defined as:

hardheartedness and coldheartedness: an absence of concern for the welfare of others

Other synonyms of hardheartedness include heartlessness.

hardheartedness (noun)	coldheartedness (noun)
an absence of concern for the welfare of others	an absence of concern for the welfare of others