Old character carrying a gun, a vagabond of yore (8)
I believe the answer is:
runagate
'a vagabond of yore' is the definition.
The definition suggests a singular noun which matches the answer.
'old character carrying a gun' is the wordplay.
'old character' becomes 'rune' (ancient symbol).
'carrying' indicates putting letters inside.
'gun' becomes 'gat' (US informal term for a gun).
'a'+'gat'='agat'
'rune' enclosing 'agat' is 'RUNAGATE'.
Can you help me to learn more?
(Another definition for runagate that I've seen is " Vagabond".)