Secure everything to detain bailiff (5)
I believe the answer is:
reeve
'bailiff' is the definition.
(I've seen this before)
'secure everything to detain' is the wordplay.
'to detain' says the answer is hidden in the clue (detain can mean to hold or imprison).
'REEVE' can be found hidden inside 'secure everything'.
(Other definitions for reeve that I've seen before include "Saxon magistrate" , "Pass a rope through a block" , "The bailiff to run a rope through" , "Old judge" , "Chief magistrate, formerly" .)