Free entry regularly accessed by politician (5)
I believe the answer is:
empty
'free' is the definition.
(both can mean unoccupied)
'entry regularly accessed by politician' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'accessed by' is an insertion indicator (inserted letters gain access to the word).
'politician' becomes 'mp' (Member of Parliament).
The alternate letters of 'entry' are 'ety'.
'ety' enclosing 'mp' is 'EMPTY'.
(Other definitions for empty that I've seen before include "Evacuate" , "Dead man" , "Vacant - futile - blank" , "Containing nothing" , "(Of words) insincere" .)