Distant medium smallholding (4)
I believe the answer is:
farm
'smallholding' is the definition.
(I've seen this before)
'distant medium' is the wordplay.
'distant' becomes 'far' (similar in meaning).
'medium' becomes 'm' (as in UK clothing sizes).
'far'+'m'='FARM'
(Other definitions for farm that I've seen before include "Cultivate the land" , "Agricultural unit" , "Cold Comfort --" , "See 5" , "Rural workplace" .)