Fastener on belt or shoe (6)
I believe the answer is:
buckle
'fastener on belt or shoe' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for buckle that I've seen before include "Crumple under pressure, or belt fastener" , "Fastener on belt or shoe" , "Shoe or belt fastening" , "Bend - warp" , "Bend out of shape" .)