merriment vs fun

merriment and fun both are nouns.

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

As nouns, merriment and fun are synonyms defined as:

Other synonyms of merriment include playfulness.

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