I believe the answer is:
'prise' is the definition.
(I know that prise can be written as lever)
This is all the clue.
(Other definitions for lever that I've seen before include "Revel (anag.)" , "exert force, in a way" , "Revel in lifting bar" , "Lifting bar pivoted on a fulcrum" , "Rigid bar pivoting about a fulcrum" .)