warn
US /wɔːrn/
UK /wɔːrn/

1.
avisar, advertir
to inform someone in advance of a possible danger, problem, or unpleasant situation
:
•
We tried to warn them about the approaching storm.
Tentamos avisá-los sobre a tempestade que se aproximava.
•
I warned him not to touch the hot stove.
Eu o avisei para não tocar no fogão quente.
2.
aconselhar, informar
to give someone advice or information about something, especially something that might be useful or helpful
:
•
The doctor warned him against smoking.
O médico o advertiu contra o fumo.
•
She warned me that the road would be slippery.
Ela me avisou que a estrada estaria escorregadia.