The complaint of a person possessing nothing (4)
I believe the answer is:
moan
'the complaint' is the definition.
(a moan is a complaint or objection)
'person possessing nothing' is the wordplay.
'person' becomes 'man' (man is a kind of person).
'possessing' indicates putting letters inside.
'nothing' becomes 'O' (looks like zero - 0).
'man' going around 'o' is 'MOAN'.
'of a' is the link.
(Other definitions for moan that I've seen before include "Complain, groan" , "Keen" , "Murmur of pain; grumble" , "Expression of suffering" , "Bewail" .)