Came round to get weapon (4)
I believe the answer is:
mace
'weapon' is the definition.
'came round' is the wordplay.
'round' is an anagram indicator.
'came' anagrammed gives 'MACE'.
'to get' acts as a link.
(Other definitions for mace that I've seen before include "put on the rack?" , "Ceremonial staff or kind of spice" , "Spiked club" , "Medieval weapon or kind of spice" , "Spice; heavy club" .)