Wary or prudent (8)
I believe the answer is:
cautious
I believe this clue is a double definition.
'wary' is the first definition.
(similar in meaning)
'prudent' is the second definition.
(I've seen this in another clue)
(Other definitions for cautious that I've seen before include "'Watchful, prudent (8)'" , "Wary or prudent" , "Keen to avoid danger" , "Careful, shrewd" , "Unadventurous" .)