Spike covering new weapon (5)
I believe the answer is:
lance
'weapon' is the definition.
(lance is a kind of weapon)
'spike covering new' is the wordplay.
'spike' becomes 'lace' ('lace' can be a synonym of 'spike').
'covering' means one lot of letters goes inside another.
'new' becomes 'n'.
'lace' enclosing 'n' is 'LANCE'.
(Other definitions for lance that I've seen before include "Old cavalry weapon" , "Clean (anag) -- weapon" , "Surgical knife" , "Spear for a horse-soldier" , "Shafted weapon used on horseback" .)