Oversight describing short politician as bore (7)
I believe the answer is:
calibre
'bore' is the definition.
(I know that bore can be written as calibre)
'oversight describing short politician' is the wordplay.
'oversight' becomes 'care' (both can mean looking after something).
'describing' indicates putting letters inside (describe can mean to form the outline of).
'short politician' becomes 'lib' (short for liberal).
'care' placed around 'lib' is 'CALIBRE'.
'as' acts as a link.
(Other definitions for calibre that I've seen before include "gifts" , "Diameter of a gun barrel" , "bore on the Tube?" , "weapon's bore?" , "Bullet size" .)