Dull answer by politician study must include (6)
I believe the answer is:
dampen
'dull' is the definition.
(I know that dull can be written as dampen)
'answer by politician study must include' is the wordplay.
'answer' becomes 'a' (abbreviation eg in Q and A).
'by' says to put letters next to each other.
'politician' becomes 'MP' (Member of Parliament).
'study' becomes 'den' (term for a study or office).
'must include' indicates putting letters inside.
'a'+'mp'='amp'
'amp' placed inside 'den' is 'DAMPEN'.
(Other definitions for dampen that I've seen before include "get a bit wet" , "Stifle" , "Apply liquid!" , "Make moist or subdued" , "Discourage in moist manner" .)