Habitually sullen person (8)

I believe the answer is:

sourpuss

'habitually sullen person' is the definition.
(I've seen this before)

This is all the clue.

(Other definitions for sourpuss that I've seen before include "Habitually sullen person" , "Bad-tempered person" , "One has a habitually sullen expression" , "Grumbler" , "Miserable so-and-so" .)

I've seen this clue in The Times and 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.