An easy catch for a poser (6)
I believe the answer is:
sitter
I believe this is a double definition.
'an easy catch' is the first definition.
'a poser' is the second definition.
(I have seen 'A poser' mean 'sitter' so perhaps 'poser' could also mean 'sitter')
'for' is the link.
(Other definitions for sitter that I've seen before include "One minds the baby" , "one can't stand?" , "broody type" , "Child minder, sounds sedentary" , "Child-minder of sedentary disposition" .)