warn

(verb) notify of danger, potential harm, or risk. Examples: "The director warned him that he might be fired." "The doctor warned me about the dangers of smoking."

(verb) admonish or counsel in terms of someone's behavior. Synonyms: discourage, admonish, monish. Examples: "I warned him not to go too far." "I warn you against false assumptions." "She warned him to be quiet."

(verb) ask to go away. Example: "The old man warned the children off his property."

(verb) notify, usually in advance. Example: "I warned you that i would ask some difficult questions."