Catalonian swallow's claw (5)
I believe the answer is:
talon
'claw' is the definition.
(I know that talon is a type of claw)
'catalonian swallow's' is the wordplay.
'swallow's' indicates a hidden word (I've seen 'swallowing' mean this).
'TALON' is hidden in the letters of 'catalonian'.
(Other definitions for talon that I've seen before include "ogee moulding" , "Hooker" , "One hooked on bird" , "one that grips" , "Claw of a bird of prey" .)