(chamada despertador/para acordar, alerta) A telephone call that one requests to occur at a specific time in order to be woken up, especially in a hotel.
A sign or warning that alerts one to negative or dangerous behavior or circumstances: “Her personal life was spiraling out of control . . . and her brush with death came as a wake-up call”.
A portentous event, report, or situation that brings an issue to immediate attention. For example, The rise in unemployment has given a wake-up call to state governments, or The success of the online subscription is a wake-up call to publishers.