Sounds like bad-tempered greengrocer's cross (4)

I believe the answer is:

ugli

I'm a little stuck... Click here to teach me more about this clue!

'cross' is the definition.
(I've seen this before)

I cannot understand how the remainder of the clue works.

(Other definitions for ugli that I've seen before include "Cross between Seville orange, grapefruit and tangerine" , "Sweet variety of tangelo from Jamaica" , "(Repulsive-looking?) fruit" , "West Indian citrus fruit" , "Orange-grapefruit cross" .)

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.