fun vs recreation

fun and recreation both are nouns.

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

As nouns, recreation is a hypernym of fun; that is, recreation is a word with a broader meaning than fun:

Other hypernyms of fun include diversion.

fun (noun)	recreation (noun)
activities that are enjoyable or amusing	an activity that diverts or amuses or stimulates
violent and excited activity	activity that refreshes and recreates; activity that renews your health and spirits by enjoyment and relaxation
a disposition to find (or make) causes for amusement
verbal wit or mockery (often at another's expense but not to be taken seriously)