Most of monarchy exclude this means of leverage (7)
I believe the answer is:
crowbar
'this means of leverage' is the definition.
'most of monarchy exclude' is the wordplay.
'most of' means to remove the last letter.
'monarchy' becomes 'crown'.
'exclude' becomes 'bar' ('bar' can be a synonym of 'exclude').
'crown' with its final letter taken off is 'crow'.
'crow'+'bar'='CROWBAR'
(Other definitions for crowbar that I've seen before include "In America, one prizes" , "Heavy iron lever" , "one able to afford purchase" , "Levering tool" , "The means to get leverage" .)