Weapon unsuited to very close combat! (5)
I believe the answer is:
lance
'weapon' is the definition.
(lance is a kind of weapon)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for lance that I've seen before include "fish" , "Cut open" , "A horse soldier's spear" , "steel" , "corporal may have at the front" .)