Order inflicted on a private (12)
I believe the answer is:
confidential
'private' is the definition.
('confidential' can be similar in meaning to 'private')
'order inflicted on a' is the wordplay.
'order' indicates an anagram.
'inflicted'+'on'+'a'='inflictedona'
'inflictedona' anagrammed gives 'CONFIDENTIAL'.
(Other definitions for confidential that I've seen before include "Intended to be kept secret" , "Graham Greene's agent" , "Classified" , "Like T.S. Eliot's clerk" , "Inflicted on a (anag) - private" .)