rhapsody vs joyfulness

rhapsody and joyfulness both are nouns.

Word	Noun	Adjective	Verb	Adverb
rhapsody	Yes	No	No	No
joyfulness	Yes	No	No	No

As nouns, joyfulness is a hypernym of rhapsody; that is, joyfulness is a word with a broader meaning than rhapsody:

Other hypernyms of rhapsody include joy, joyousness.

rhapsody (noun)	joyfulness (noun)
(in ancient Greece) an epic poem adapted for recitation	the emotion of great happiness
(music) a free instrumental composition in one extended movement; typically emotional or exuberant in character
an enthusiastic expression of emotion