Charlie once more forgetting name for weapon (7)
I believe the answer is:
assagai
'weapon' is the definition.
(assagai is a kind of weapon)
'charlie once more forgetting name' is the wordplay.
'charlie' becomes 'ass' (both can mean a foolish person).
'once more' becomes 'again' (synonyms).
'forgetting' suggests deleting specific letters.
'name' becomes 'n' (common abbreviation e.g. on forms).
'again' with 'n' taken out is 'agai'.
'ass'+'agai'='ASSAGAI'
'for' is the link.
(Other definitions for assagai that I've seen before include "Spear used in S Africa" , "Weapon" , "Zulu weaponry" .)