Clip or catch (8)
I believe the answer is:
fastener
This clue is a double definition.
'clip' is the first definition.
(I've seen this in another clue)
'catch' is the second definition.
(thesaurus)
(Other definitions for fastener that I've seen before include "Clip, catch or other means of fixing securely" , "Device for joining things together" , "Device that closes clothes - may be a zip" , "Securing clip" , "Eg, clip or catch" .)