Pears used as weapon (5)
I believe the answer is:
spear
'weapon' is the definition.
(I know that spear is a type of weapon)
'pears used' is the wordplay.
'used' indicates an anagram.
'pears' is an anagram of 'SPEAR'.
'as' is the link.
(Other definitions for spear that I've seen before include "Javelin or harpoon" , "A bit of asparagus" , "pierce with this?" , "stick" , "asparagus for example" .)