Long-standing resentment (7)

I believe the answer is:

rancour

(Other definitions for rancour that I've seen before include "Long-lasting bitterness" , "Bitterness and ill will" , "Bitterness and bile" , "'Bitterness, resentment (7)'" , "Acrimony" .)

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.