He'll look out for a tin opener (in the safe?) (5)
I believe the answer is:
peter
'safe?' is the definition.
(slang term for a safe)
'he'll look out for a tin opener in the' is the wordplay.
I cannot really see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
'look' could be 'peer' (to peer at something is to look at it) and 'peer' is located in the remaining letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for peter that I've seen before include "Saint at the Pearly Gates?" , "Safe - name for a man" , "emperor" , "till down under" , "Rock-like apostle" .)