Staff guarding the new chopper (7)
I believe the answer is:
machete
'chopper' is the definition.
(blade for chopping things down)
'staff guarding the new' is the wordplay.
'staff' becomes 'mace' (a mace is a ceremonial staff or stick).
'guarding' indicates putting letters inside (inserted letters are protected or guarded).
'new' indicates an anagram.
'the' with letters rearranged gives 'het'.
'mace' going around 'het' is 'MACHETE'.
(Other definitions for machete that I've seen before include "Broad heavy knife common in Central America" , "Broad heavy knife used in S American jungles" , "cutter" , "The mace (anag.)" , "Broad heavy knife used in S America" .)