When you hypnotize someone, you draw him into a mental state that is receptive to suggestion. If you are looking to break a bad habit like cigarette smoking, ask someone to hypnotize you.
To hypnotize is to induce a calm, focused state in one's self or in another person. The state is called hypnosis, and a person who can do this for someone else is a hypnotist. The word hypnotize comes from the Greek hypnotikos, "inclined to sleep or putting to sleep," and popular ideas of hypnosis reflect a kind of half-asleep state. In reality, when you hypnotize someone, the person remains awake and intently focused.