Pears used as a weapon (5)
I believe the answer is:
spear
'a weapon' is the definition.
(spear is a kind of weapon)
'pears used' is the wordplay.
'used' indicates anagramming the letters.
'pears' with letters rearranged gives '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" .)