O!
Placed at the end of sentences for emphasis and effect e.g. I go broke bottle for yua head O!
Oba
Traditional ruler
Oga
Person in charge see Big Man
Okada
Name of a Nigerian Airline. 2. Motor cycle taxi. See By air
One day one day
One of these days. Used as a warning for those involved in dodgy acts e.g One day one day monkey go go market e no go come back meaning everyday for the thief one day for the owner
Open eye
Wise up
Open mouth
Talk e.g Abeg no open mouth laik dat
Open ya sense
Use your intelligence
Oyinbo
Foreigner (Yoruba)