Hustle son on cold walk (8)
I believe the answer is:
scramble
'hustle' is the definition.
(thesaurus)
'son on cold walk' is the wordplay.
'son' becomes 's'.
'on' means one lot of letters go next to another.
'cold' becomes 'c' (eg on taps).
'walk' becomes 'ramble' (ramble is a kind of walk**).
's'+'c'+'ramble'='SCRAMBLE'
(Other definitions for scramble that I've seen before include "Cycle event" , "keep communication secret" , "make a message unintelligible" , "Make jumbled" , "Interfere with signals" .)