playfulness vs levity

playfulness and levity both are nouns.

Word	Noun	Adjective	Verb	Adverb
playfulness	Yes	No	No	No
levity	Yes	No	No	No

As nouns, levity is a hypernym of playfulness; that is, levity is a word with a broader meaning than playfulness:

playfulness (noun)	levity (noun)
activities that are enjoyable or amusing	a manner lacking seriousness
a disposition to find (or make) causes for amusement	feeling an inappropriate lack of seriousness
a festive merry feeling