Snide comment (4)
I believe the answer is:
barb
'snide comment' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for barb that I've seen before include "Point of fish-hook - gibe" , "Kind of thorn or wounding remark" , "Woundingly pointed remark" , "added to wire?" , "Thorn or spike" .)