Monarch's order (4)

I believe the answer is:

fiat

(Other definitions for fiat that I've seen before include "Decree; Italian car make" , "mandate" , "Decree or official permission" , "Command" , "Arbitrary order" .)

I've seen this clue in The Washington Post.

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.