He was a 'traitor' who betrayed his country by selling military secrets to the enemy.
He 'turned traitor'. [=he became a traitor; he betrayed his country/friends]
She has been called a 'traitor' to the liberal party's cause.
(..) That's how it's gonna be, man. You think that's good? That's how you want to do it? That's how you want to leave it? I just have to find a purpose. A traitor? A Judas? Why? What was it about? Michael! You want to go inside, bro? We gonna start soon. Fella won some local school comp. (..)2014 The Dark Horse