Push the bottom off a big spade (5)
I believe the answer is:
shove
'push' is the definition.
(I know that shove is a kind of push)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for shove that I've seen before include "Barge" , "Push or propel" , "Push roughly" , "Push (or what it comes to!)" , "- - -halfpenny (pub game)" .)