Inmate on a disorderly discharge (9)
I believe the answer is:
emanation
'discharge' is the definition.
(thesaurus)
'inmate on a disorderly' is the wordplay.
'disorderly' indicates an anagram.
'inmate'+'on'+'a'='inmateona'
'inmateona' anagrammed gives 'EMANATION'.
(Other definitions for emanation that I've seen before include "Something given off" , "Pouring out" , "Something flowing out from a source" , "Issue" , "Something issuing from a source" .)