coldheartedness vs hardheartedness

coldheartedness and hardheartedness both are nouns.

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

As nouns, coldheartedness and hardheartedness are synonyms defined as:

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

Other synonyms of coldheartedness include heartlessness.

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