Government plot is deviously taking in one Conservative (8)
I believe the answer is:
politics
'government' is the definition.
(government or governing is political activity)
'plot is deviously taking in one conservative' is the wordplay.
'deviously' indicates an anagram (I've seen this in other clues).
'taking in' means one lot of letters goes inside another.
'one conservative' becomes 'ic' (I can't explain this - if you can you should believe this answer much more).
'plot'+'is'='plotis'
'plotis' is an anagram of 'polits'.
'polits' going around 'ic' is 'POLITICS'.
Can you help me to learn more?
(Other definitions for politics that I've seen before include "Affairs of state" , "The business of government" , "Westminster activity" , "The subject of government and parties" , "Tips coil (anag.)" .)