Pears used as a weapon (5)
I believe the answer is:
spear
'a weapon' is the definition.
(I know that spear is a type of weapon)
'pears used' is the wordplay.
'used' indicates anagramming the letters.
'pears' is an anagram of 'SPEAR'.
'as' is the link.
(Other definitions for spear that I've seen before include "Stabbing, throwing, weapon" , "asparagus for example" , "Sharp weapon" , "stick" , "Impale" .)