Rank administered by police force (6)
I believe the answer is:
rancid
'rank' is the definition.
(I've seen this before)
'administered by police force' is the wordplay.
'administered' becomes 'ran' (run can mean to administer or control).
'by' says to put letters next to each other.
'police force' becomes 'CID' (abbreviation for Criminal Investigation Department).
'ran'+'cid'='RANCID'
(Other definitions for rancid that I've seen before include "Sour like stale grease 96)" , "(Of fatty foods) gone off" , "Smelling or tasting of stale fat" , "Rank, high" , "Tasting or smelling sour, butter say" .)