bagatelle vs triviality

bagatelle and triviality both are nouns.

Word	Noun	Adjective	Verb	Adverb
bagatelle	Yes	No	No	No
triviality	Yes	No	No	No

As nouns, triviality is a hypernym of bagatelle; that is, triviality is a word with a broader meaning than bagatelle:

Other hypernyms of bagatelle include small beer, trifle, trivia.

bagatelle (noun)	triviality (noun)
a table game in which short cues are used to knock balls into holes that are guarded by wooden pegs; penalties are incurred if the pegs are knocked over	something of small importance
something of little value or significance	the quality of being unimportant and petty or frivolous
a light piece of music for piano	a detail that is considered insignificant