Push over (6)
I believe the answer is:
topple
'push over' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for topple that I've seen before include "Remove from power" , "Fall, tumble" , "Overthrow or fall headlong" , "Overbalance and fall headlong" , "(Cause to) tip over" .)