Concerned with politician concealing a plot again (5)
I believe the answer is:
remap
'plot again' is the definition.
('map' can be a synonym for 'plot' so perhaps 'remap' is OK for 'plot again')
'concerned with politician concealing a' is the wordplay.
'concerned with' becomes 're' ('re' means regarding or about).
'politician' becomes 'MP' (Member of Parliament).
'concealing' means one lot of letters goes inside another.
'mp' placed around 'a' is 'map'.
're'+'map'='REMAP'
(Other definitions for remap that I've seen before include "(In computing) change the assignment of a function to a key" , "Plot again" , "Make new plans" , "Survey (area) again" , "chart again" .)