#1 warn v. notify of danger, potential harm, or risk; "The director warned him that he might be fired"; "The doctor warned me about the dangers of smoking". wn
#2 warn v. [discourage, admonish, monish] admonish or counsel in terms of someone's behavior; "I warned him not to go too far"; "I warn you against false assumptions"; "She warned him to be quiet". wn
#3 warn v. ask to go away; "The old man warned the children off his property". wn
#4 warn v. notify, usually in advance; "I warned you that I would ask some difficult questions". wn
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