Prudence gets coarse (4)
I believe the answer is:
rude
'coarse' is the definition.
(I've seen this before)
'prudence gets' is the wordplay.
'gets' indicates a hidden word.
'RUDE' can be found hidden inside 'prudence'.
(Other definitions for rude that I've seen before include "Impolite, without consideration" , "so curt here?" , "Offensive; unpolished" , "Uncouth" , "Impolite or vulgar" .)