Earlier bribe for exploitable guards (6)
I believe the answer is:
before
'earlier' is the definition.
(synonyms)
'bribe for exploitable guards' is the wordplay.
'guards' says the answer is hidden in the clue.
'BEFORE' is hidden within 'bribe for exploitable'.
(Other definitions for before that I've seen before include "On a previous occasion" , "Earlier in time" , "In front of or previous to" , "During the period preceding" , "In sight of" .)