Sounded discourteous, and felt remorse (4)
I believe the answer is:
rued
'felt remorse' is the definition.
(I've seen this in another clue)
'sounded discourteous' is the wordplay.
'sounded' shows a homophone (sound like).
'discourteous' becomes 'rude' (I've seen this before).
'rude' sounds like 'RUED'.
'and' is the link.
(Other definitions for rued that I've seen before include "Bitterly regretted" , "was remorseful" , "'Regretted, repented (4)'" , "Was contrite about" , "Was sorry" .)