What is the meaning of warn?

verb

• Notify of danger, potential harm, or risk.
  • usage: "The director warned him that he might be fired"; "The doctor warned me about the dangers of smoking"
• Admonish or counsel in terms of someone's behavior.
  • usage: "I warned him not to go too far"; "I warn you against false assumptions"; "She warned him to be quiet"
  • synonyms: discourage, admonish, monish
• Ask to go away.
  • usage: "The old man warned the children off his property"
• Notify, usually in advance.
  • usage: "I warned you that I would ask some difficult questions"