One's right to access the land (5)
I believe the answer is:
acres
'the land' is the definition.
('acres' can be a synonym of 'land')
'one's right to access' is the wordplay.
'one's' becomes 'ace's' (ace has a value of one in some card games).
'right' becomes 'r' (common abbreviation).
'to access' is an insertion indicator (inserted letters gain access to the word).
'aces' enclosing 'r' is 'ACRES'.
(Other definitions for acres that I've seen before include "Extensive landed property (often rolling)" , "farmland maybe?" , "large area of land" , "Land area measures" , "Cares about these measurements?" .)