Officer studies information systematically displayed (9)
I believe the answer is:
constable
'officer' is the definition.
(a police officer)
'studies information systematically displayed' is the wordplay.
'studies' becomes 'cons' (to con is to study or revise).
'information systematically displayed' becomes 'table' (a table of information).
'cons'+'table'='CONSTABLE'
(Other definitions for constable that I've seen before include "See 1" , "Force member" , "English landscape painter for a policeman" , "PC" , "In England, a great painter or lowly policeman" .)