As a Verb or Adjective:
1. Not to have prepared yourself in time for something. English = (be) not ready.
Interactive:
1. Used in response to a question about when something should happen or be done to mean that you think it should not be done now, although it will have to be done at a later time. English = 'Not yet.'
As Modifier:
1. Used immediately next to a verb to mean the action has not happened up to the present time, although it probably will happen. English = not yet.