Pester military policeman during routine working (9)
I believe the answer is:
importune
'pester' is the definition.
(thesaurus)
'military policeman during routine working' is the wordplay.
'military policeman' becomes 'mp' ('MP' can be a synonym of 'military policeman').
'during' is an insertion indicator.
'working' indicates an anagram.
'routine' is an anagram of 'iortune'.
'mp' going within 'iortune' is 'IMPORTUNE'.
(Other definitions for importune that I've seen before include "make improper advances to" , "Persistently request" , "Harry" , "Hound" , "plague" .)