Spike protecting new weapon (5)
I believe the answer is:
lance
'weapon' is the definition.
(lance is a kind of weapon)
'spike protecting new' is the wordplay.
'spike' becomes 'lace' ('lace' can be a synonym of 'spike').
'protecting' indicates putting letters inside.
'new' becomes 'n'.
'lace' enclosing 'n' is 'LANCE'.
(Other definitions for lance that I've seen before include "Weapon of knights of old" , "Incise" , "Long, pointed weapon (5)." , "Shafted weapon used on horseback" , "Horseman's long spear" .)