Cutting remark in pub -- banter, initially (4)
I believe the answer is:
barb
'cutting remark' is the definition.
(I've seen this before)
'pub banter initially' is the wordplay.
'pub' becomes 'bar' (I've seen this before).
'initially' indicates taking the first letters.
The first letter of 'banter' is 'b'.
'bar'+'b'='BARB'
'in' acts as a link.
(Other definitions for barb that I've seen before include "criticism" , "Thorn or spike" , "added to wire?" , "nasty comment" , "Twisted point of hook" .)