Fastener caught edge (4)
I believe the answer is:
clip
'fastener' is the definition.
(clip is a kind of fastener)
'caught edge' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'edge' becomes 'lip' (lip is a kind of edge).
'c'+'lip'='CLIP'
(Other definitions for clip that I've seen before include "It holds items together" , "Something that holds things together - cut" , "Cut - part of film" , "sort of joint" , "Device for holding papers together" .)