joviality vs merriment

joviality and merriment both are nouns.

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

As nouns, merriment is a hypernym of joviality; that is, merriment is a word with a broader meaning than joviality:

Other hypernyms of joviality include gaiety, amiability, good humor, good humour, good temper.

joviality (noun)	merriment (noun)
a jovial nature	activities that are enjoyable or amusing
feeling jolly and jovial and full of good humor	a gay feeling