Person with honour, one that's in forever, possessing go (4,4)
I believe the answer is:
life peer
'person with honour one that's' is the definition.
I can't tell whether this defines the answer.
'forever possessing go' is the wordplay.
'forever' becomes 'lifer' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'possessing' indicates putting letters inside.
'go' becomes 'pee' (both can mean to urinate).
'lifer' going around 'pee' is 'LIFE PEER'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for life peer that I've seen before include "House of Lords member whose title cannot be inherited" , "One's entitled" , "One legislates" , "The noble lord" , "House-sitter" .)