__ of approval; favorable stamp

I believe the answer is:

seal

(Other definitions for seal that I've seen before include "A mammal; a fastening" , "Sea mammal in sale" , "marine creature" , "Settle or decide - say fate" , "See 7" .)

I've seen this clue in The Mirror.

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.