Play the politician, ousting queen (3)
I believe the answer is:
toy
'play' is the definition.
('toy' can be a synonym of 'play')
'the politician ousting queen' is the wordplay.
'the politician' becomes 'tory' (I've seen this before).
'ousting' suggests deleting specific letters.
'queen' becomes 'r' (r is abbreviation regina. e.g. in ER ).
'tory' with 'r' taken away is 'TOY'.
(Other definitions for toy that I've seen before include "Doll or teddy, say" , "Child's amusement" , "Teddy or Dolly" , "Small breed" , "Object for a child to play with" .)