Man, perhaps, is secure (6)
I believe the answer is:
island
'man perhaps' is the definition.
(man is a kind of island)
'is secure' is the wordplay.
'secure' becomes 'land' (I've seen this in other clues).
'is'+'land'='ISLAND'
(Other definitions for island that I've seen before include "'Treasure - - ' by R L Stevenson" , "Sumatra, say" , "Eg, eyot or inch" , "Eg, Anglesey, Sheppey" , "Ireland, Jersey or Iceland, say" .)