estar sobre aviso

1.
SpainLatin AmericaGeneral (Spanish-speaking world)neutralformal
- To be on alert or prepared to respond to a possible event or danger.
- To remain watchful and attentive because a risk, threat, or important development has been communicated.
2.
SpainLatin AmericaGeneral (Spanish-speaking world)neutralformal
- To have been warned or given notice about something; to be informed in advance of a circumstance or consequence.

Examples:

ES: No debe estar sobre aviso.
EN: You must not be alert.
ES: Debemos estar sobre aviso.
EN: We must just be on the alert.
ES: Todas las unidades, cualquier contacto, estar sobre aviso.
EN: All units report any contact and be advised.
ES: Deben estar sobre aviso.
EN: They should be warned.
ES: Seguramente la gente de la banda ya sabe lo que le pasó a Ángel y deben estar sobre aviso.
EN: The people from the band probably already know what happened to Ángel, and they must've been warned.
ES: *Y he aprendido lo bastante para estar sobre aviso*
EN: ♪ So I learned enough to watch my back ♪
ES: Pero hubiera preferido estar sobre aviso, y también volvieron a encontrar bastantes pruebas de infidelidad, nada realmente extraordinario.
EN: But I wish you'd forewarned me, and they found quite considerable evidence of infidelity again - nothing truly extraordinary.
ES: La policía debe estar sobre aviso.
EN: Cops must be on the take.