Prolonged reprimand (6)
I believe the answer is:
earful
'prolonged reprimand' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for earful that I've seen before include "load of wax, possibly" , "Ale fur (anag.)" , "Get this and you listen to a lot" , "A telling-off" , "Severe reprimand" .)