Vegetable shelter gets nothing in return (4)
I believe the answer is:
okra
'vegetable' is the definition.
(I know that okra is a type of vegetable)
'shelter gets nothing in return' is the wordplay.
'shelter' becomes 'ark' (I have seen 'Ancient shelter' mean 'ark' so perhaps 'shelter' could also mean 'ark').
'gets' is a charade indicator (letters next to each other).
'nothing' becomes 'O' (looks like zero - 0).
'in return' says the letters should be written in reverse (return can mean to go backwards).
'ark'+'o'='arko'
'arko' in reverse letter order is 'OKRA'.
(Other definitions for okra that I've seen before include "Ladies' fingers with edible pods" , "Bhindi or lady's finger" , "Tropical plant with edible pods" , "Lady's fingers; gumbo; bhindi" , "Green pods, in stews" .)