Naive politician (5)
I believe the answer is:
green
I believe this clue is a double definition.
'naive' is the first definition.
(similar in meaning)
'politician' is the second definition.
(eg member of the Green Party)
(Other definitions for green that I've seen before include "Politician perhaps" , "Colour of malachite" , "Inexperienced - olive coloured" , "The colour of inexperience" , "Like lettuce" .)