Politician holding a chart (3)
I believe the answer is:
map
'chart' is the definition.
('map' can be a synonym of 'chart')
'politician holding a' is the wordplay.
'politician' becomes 'mp' (**).
'holding' indicates putting letters inside.
'mp' enclosing 'a' is 'MAP'.
(Other definitions for map that I've seen before include "(Make a) geographical representation" , "Representation of earth's surface as a guide" , "Chart" , "Diagram of part of the earth's surface" , "Geographical plan" .)