lightness vs joyfulness

lightness and joyfulness both are nouns.

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

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

Other hypernyms of lightness include joy, joyousness.

lightness (noun)	joyfulness (noun)
the trait of being lighthearted and frivolous	the emotion of great happiness
the visual effect of illumination on objects or scenes as created in pictures
the property of being comparatively small in weight
having a light color
the gracefulness of a person or animal that is quick and nimble
a feeling of joy and pride