compassionateness vs sympathy

compassionateness and sympathy both are nouns.

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

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

compassionateness: a deep awareness of and sympathy for another's suffering
sympathy: sharing the feelings of others (especially feelings of sorrow or anguish)

Other hypernyms of compassionateness include fellow feeling.

compassionateness (noun)	sympathy (noun)
a deep awareness of and sympathy for another's suffering	an inclination to support or be loyal to or to agree with an opinion
	sharing the feelings of others (especially feelings of sorrow or anguish)
	a relation of affinity or harmony between people; whatever affects one correspondingly affects the other