Green’s Dictionary of Slang

oke! excl.

all right!

1930		J. Lait Gangster Girl 134: ‘Oke!’ he bit off sharply. ‘Dem two blokes won’t bother us.’.
1932		D. Hammett ‘A Man Called Spade’ in Nightmare Town (2001) 298: The gray-faced man said, ‘Oke.’.
1943		J. Phelan Letters from the Big House 51: ‘Oke,’ was all Gloster said.