Knightly weapon for Percival perhaps? (5)
I believe the answer is:
lance
I believe this clue is a double definition.
'knightly weapon' is the first definition.
(I've seen this before)
'for percival perhaps?' is the second definition.
(as in comedian Percival Lance)
(Other definitions for lance that I've seen before include "Spear carried by mounted soldier" , "A horse soldier's spear" , "Long-shafted weapon" , "Weapon of knights of old" , "Spear for a horse-soldier" .)