Shove top usher inside (4)
I believe the answer is:
push
'shove' is the definition.
(I know that shove is a more specific form of the action push)
'top usher inside' is the wordplay.
'inside' indicates a hidden word.
'PUSH' is hidden within 'top usher'.
(Other definitions for push that I've seen before include "Try to sell" , "Illegally supply" , "What often proverbially comes to "shove"?" , "See 8" , "Energy" .)