Chance to forgo start of gruelling walk (5)
I believe the answer is:
amble
'walk' is the definition.
(ambling is a kind of walking)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for amble that I've seen before include "Wander casually" , "Blame for leisurely walk" , "Casual walk" , "Swan" , "Dawdle" .)