Constable — fine one — recruited by troubled force (7)
I believe the answer is:
officer
'constable' is the definition.
(thesaurus)
'fine one recruited by troubled force' is the wordplay.
'fine' becomes 'f' (abbreviation).
'one' becomes 'i' (Roman numeral).
'recruited by' means one lot of letters goes inside another.
'troubled' indicates anagramming the letters.
'f'+'i'='fi'
'force' is an anagram of 'ofcer'.
'fi' placed within 'ofcer' is 'OFFICER'.
(Other definitions for officer that I've seen before include "A commissioned soldier" , "Person with authority in the forces" , "Holder of a post" , "Commissioned member of the services" , "Maybe society treasurer" .)