Relish – impertinence (5)
I believe the answer is:
sauce
This clue is a double definition.
'relish' is the first definition.
(relish can mean a sauce or dressing)
'impertinence' is the second definition.
(I've seen this in another clue)
(Other definitions for sauce that I've seen before include "Cause (anag.)" , "Relish or impertinence" , "Informal impudence or food flavouring" , "''Hunger is good .....''" , "Flavourful relish" .)