<p><strong>Verb (used without object):</strong></p><ul><li>to make a humming, buzzing, or hissing sound, as an object passing swiftly through the air.</li><li>to move or rush with such a sound: The angry hornets whizzed by in a cloud.</li></ul><p><strong>Verb (used with object):</strong></p><ul><li>to cause to whiz.</li><li>to treat with a whizzer.</li></ul><p><strong>Noun (Informal):</strong></p><ul><li>a person who is quite good at a particular activity, in a certain field, etc.: She's a whiz at math.</li><li>the sound of a whizzing object.</li><li>a swift movement producing such a sound.</li></ul>