Hello! about to claim politician is naughty (6)
I believe the answer is:
impish
'naughty' is the definition.
(I've seen this before)
'hello about to claim politician is' is the wordplay.
'hello' becomes 'hi' (synonyms).
'about' is a reversal indicator.
'to claim' is an insertion indicator (inserted letters are claimed or taken in).
'politician' becomes 'MP' (Member of Parliament).
'hi' backwards is 'ih'.
'mp'+'is'='mpis'
'ih' going around 'mpis' is 'IMPISH'.
(Other definitions for impish that I've seen before include "Playful" , "troublesome" , "Mischievous like small devil" , "Teasingly mischievous" , "Mischievous like small fairy" .)