Buckle (4)
I believe the answer is:
warp
'buckle' is the definition.
(I know that buckle can be written as warp)
This is the entire clue.
(Other definitions for warp that I've seen before include "Crane fly larva" , "Distort, ship's rope" , "Make bent or twisted" , "Pervert - distort" , "Buckle" .)