Tread on (7)
I believe the answer is:
trample
'tread on' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for trample that I've seen before include "Crush with the feet" , "Flatten" , "Ruthlessly crush -- nut performed a lot (anag)" , "Heedlessly tread down" , "Walk heavily or roughly" .)