Learn how to say Frivolousness correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word frivolous:
not having any serious purpose or value:
frivolous ribbons and lacy frills
rules to stop frivolous lawsuits
(of a person) carefree and superficial:
the frivolous, fun-loving flappers of the twenties
late Middle English: from Latin frivolus ‘silly, trifling’ + -ous