With part of this grid and 46-Across, flat finale (5)

I believe the answer is:

antic

(Other definitions for antic that I've seen before include "Eccentric once" , "Caper, trick" , "Absurd action" , "Old clown" , "Playful or mischievous act" .)

I've seen this clue in the Universal.

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.