Was sorry to sound a bit crude (4)
I believe the answer is:
rued
'was sorry' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for rued that I've seen before include "Was sorry" , "Was contrite about" , "Bitterly regretted" , "'Regretted, repented (4)'" , "was remorseful" .)