A nun cries out for cover (9)
I believe the answer is:
insurance
'cover' is the definition.
(I've seen this before)
'a nun cries out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'a'+'nun'+'cries'='anuncries'
'anuncries' with letters rearranged gives 'INSURANCE'.
'for' is the link.
(Other definitions for insurance that I've seen before include "Protection against a future eventuality" , "Such a policy guarantees" , "One's questioned taking this out" , "security" , "Guarantee of compensation in return for a premium" .)