Reportedly regretted being impolite (4)
I believe the answer is:
rude
'impolite' is the definition.
(similar in meaning)
'reportedly regretted' is the wordplay.
'reportedly' indicates a 'sounds like' (homophone) clue.
'regretted' becomes 'rued' ('rue' can be a synonym of 'regret').
'rued' sounds like 'RUDE'.
'being' acts as a link.
(Other definitions for rude that I've seen before include "Discourteous or unrefined" , "Coarse, unpolished" , "Coarse or discourteous" , "having no manners?" , "so curt here?" .)