Prune in cold sauce (4)
I believe the answer is:
clip
'prune' is the definition.
(I know that prune can be written as clip)
'cold sauce' is the wordplay.
'cold' becomes 'C' (eg on taps).
'sauce' becomes 'lip' (both can mean insolence).
'c'+'lip'='CLIP'
'in' acts as a link.
(Other definitions for clip that I've seen before include "Shorten" , "Fastener; cut short" , "Film segment" , "Trim the catridge container?" , "Prune" .)