Look closely around opening of the safe (5)
I believe the answer is:
peter
'safe' is the definition.
(I've seen this in other clues)
'look closely around opening of the' is the wordplay.
'look closely' becomes 'peer' (I've seen this before).
'around' indicates putting letters inside.
'opening of' indicates taking the first letters.
The initial letter of 'the' is 't'.
'peer' going around 't' is 'PETER'.
(Other definitions for peter that I've seen before include "Saint's name" , "Dwindle away to nothing" , "Safe - name for a man" , "- Grimes (Britten)" , "Man's name" .)