Fishhook feature (4)
I believe the answer is:
barb
'fishhook feature' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for barb that I've seen before include "criticism" , "Point of fish-hook - gibe" , "Cruel remark" , "Aggressive remark directed at a person" , "Backward projecting point of an arrowhead" .)