fun vs playfulness

fun and playfulness both are nouns.

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

As nouns, fun and playfulness are synonyms defined as:

Other synonyms of fun include merriment.

As nouns, fun and playfulness are synonyms defined as:

fun and playfulness: a disposition to find (or make) causes for amusement

fun (noun)	playfulness (noun)
activities that are enjoyable or amusing	activities that are enjoyable or amusing
violent and excited activity	a disposition to find (or make) causes for amusement
a disposition to find (or make) causes for amusement	a festive merry feeling
verbal wit or mockery (often at another's expense but not to be taken seriously)