soulfulness vs soul

soulfulness and soul both are nouns.

Word	Noun	Adjective	Verb	Adverb
soulfulness	Yes	No	No	No
soul	Yes	No	No	No

As nouns, soulfulness and soul are synonyms defined as:

soulfulness (noun)	soul (noun)
deep feeling or emotion	a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential
	the human embodiment of something
	a secular form of gospel that was a major Black musical genre in the 1960s and 1970s
	deep feeling or emotion
	the immaterial part of a person; the actuating cause of an individual life