Idiot for example with excellent weapon (7)
I believe the answer is:
assegai
'weapon' is the definition.
(assegai is a kind of weapon)
'idiot for example with excellent' is the wordplay.
'idiot' becomes 'ass' (both can mean a stupid person).
'for example' becomes 'e.g.' (short for 'exempli gratia', 'for example' in Latin).
'with' means one lot of letters go next to another.
'excellent' becomes 'ai' (resembles 'A1', old-fashioned term for excellent).
'ass'+'eg'+'ai'='ASSEGAI'
(Other definitions for assegai that I've seen before include "spear made from wood" , "Sea gas I convert to a Zulu spear" , "Spear of the Bantu-speaking people of Africa" , "something pointed" , "Ages as I threw the spear" .)