Prudence gets discourteous (4)
I believe the answer is:
rude
'discourteous' is the definition.
(I've seen this in another clue)
'prudence gets' is the wordplay.
'gets' says the answer is hidden in the clue.
'RUDE' can be found hidden inside 'prudence'.
(Other definitions for rude that I've seen before include "having no manners?" , "Impolite; unpolished" , "Offensively impolite" , "Offensive; unpolished" , "lacking refinement" .)