Hamper that's opened by politician Balls? (6)
I believe the answer is:
impede
'hamper' is the definition.
(I know that hamper can be written as impede)
'that's opened by politician balls?' is the wordplay.
'that's' becomes 'ie'.
'opened by' indicates putting letters inside (some letters open a gap in others).
'politician' becomes 'MP' (Member of Parliament).
'balls?' becomes 'ed' (I've seen this in other clues).
'mp'+'ed'='mped'
'ie' enclosing 'mped' is 'IMPEDE'.
(Other definitions for impede that I've seen before include "Delay or obstruct" , "Cramp" , "Hinder, form an obstacle to" , "Hinder, inhibit" , "Slow" .)