Fellow member in smallholding (4)
I believe the answer is:
farm
'smallholding' is the definition.
(I've seen this before)
'fellow member' is the wordplay.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'member' becomes 'arm' (arm is a kind of member**).
'f'+'arm'='FARM'
'in' acts as a link.
(Other definitions for farm that I've seen before include "Rural establishment" , "Country workplace" , "agricultural centre" , "Raise crops/livestock" , "Rural workplace" .)