Slim pedestrian carrying hamper (6)
I believe the answer is:
impede
'hamper' is the definition.
(I've seen this before)
'slim pedestrian carrying' is the wordplay.
'carrying' says the answer is hidden in the clue.
'IMPEDE' can be found hidden inside 'slim pedestrian'.
(Other definitions for impede that I've seen before include "Handicap" , "Cramp" , "Delay progress of (something)" , "Hinder, form an obstacle to" , "Obstruct, hold up progress" .)