Catholic shone out when selected (6)
I believe the answer is:
chosen
'selected' is the definition.
('chosen' can be similar in meaning to 'selected')
'catholic shone out' is the wordplay.
'catholic' becomes 'c' (abbreviation as in RC for Roman Catholic).
'out' indicates an anagram (out can mean wrong or inaccurate).
'shone' with letters rearranged gives 'hosen'.
'c'+'hosen'='CHOSEN'
'when' is the link.
(Other definitions for chosen that I've seen before include "Selected, picked" , "Selected, preferred" , "part of Asia once" , "If you're one of these few, you're very privileged" , "Select" .)