warns
v.v. to tell someone about a possible danger or problem so they can avoid it. You do this to keep people safe or prepared.
v. to inform someone in advance of an impending danger, problem, or other unpleasant circumstance. Takes a direct object or a 'that' clause.
The sign warns drivers about the sharp turn ahead.
The weather report warns that a heavy storm will arrive late tonight, so we should stay indoors.
The report warns of a significant decline in biodiversity if current land-use policies remain unchanged over the next decade, urging immediate legislative intervention.
Transitive verb; often takes the preposition 'of' or 'about' before a noun, or is followed by a 'that' clause.
He warned to me about the dog.He warned me about the dog.Warn is a transitive verb and does not take the preposition 'to' before the person being warned.