Man perhaps lives life on the outside (4)
I believe the answer is:
isle
'man perhaps' is the definition.
(I've seen this before)
'lives life on the outside' is the wordplay.
'lives' becomes 'is' ('be' can be a synonym of 'live').
'on the outside' suggests removing the centre.
'life' with its centre removed is 'le'.
'is'+'le'='ISLE'
(Other definitions for isle that I've seen before include "One surrounded by water" , "eg Man, Wight" , "A poetic island" , "eg Capri" , "eg Skye" .)