Frivolous behaviour (6)

I believe the answer is:

levity

(Other definitions for levity that I've seen before include "Flippant attitude to serious matters" , "Light-heartedness" , "Frivolity, lightweight laughter" , "Light quality" , "Frivolous tendency" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.