Fruits' regrettable transience (10)

I believe the answer is:

nectarines

'fruits'' is the definition.
(nectarine is a kind of fruit)

'regrettable transience' is the wordplay.
'regrettable' indicates anagramming the letters.
'transience' anagrammed gives 'NECTARINES'.

I've seen this clue in The Everyman puzzle in The Observer.

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.