1. A statement of an intention to inflict pain, injury, damage, or other hostile action on someone in retribution for something done or not done.
He made a threat against the witness.
Ele fez uma ameaça contra a testemunha.
2. A person or thing likely to cause damage or danger.
Climate change is a major threat to our planet.
A mudança climática é uma grande ameaça para nosso planeta.
3. An indication or sign of something unwelcome or unpleasant coming.
There was a threat of rain in the forecast.
Havia uma ameaça de chuva na previsão do tempo.