1. Command form of 'despertar' (to wake up); used to tell someone to wake up or to become alert
Wake up! You're going to be late for school.
Desperta-te! Vais chegar atrasado à escola.
2. Figuratively, to become aware or conscious of something
Wake up to reality and stop living in illusions.
Desperta-te para a realidade e deixa de viver em ilusões.