Walk about a mile past, roughly (5)
I believe the answer is:
stamp
'walk' is the definition.
(stamping is a kind of walking)
'about a mile past roughly' is the wordplay.
'about' means one lot of letters goes inside another.
'a mile' becomes 'm' (common abbreviation).
'roughly' indicates anagramming the letters.
'past' is an anagram of 'stap'.
'm' placed within 'stap' is 'STAMP'.
(Other definitions for stamp that I've seen before include "squash?" , "Bring foot down hard" , "Impress (a pattern)" , "Postal label" , "Official mark; bang (foot)" .)