Some claim pedestrians block progress (6)
I believe the answer is:
impede
'block progress' is the definition.
'impede' can be an answer for 'block' (synonyms). I am not sure about the 'progress' bit.
'some claim pedestrians' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'IMPEDE' can be found hidden inside 'claim pedestrians'.
Can you help me to learn more?
(Other definitions for impede that I've seen before include "Put obstacle in the way, hinder" , "Obstruct or thwart" , "Hinder, be obstructive" , "Block progress of (something)" , "Hinder, form an obstacle to" .)