When you're dizzy, you have a spinning or woozy sensation — you might even feel like you'l fall over. You'll probably feel dizzy for a while when you get off the whirling tea cup ride at the fair.
Some people feel dizzy when they're up high, either on a ladder or at the top of a tall building or bridge. Others only get dizzy when they're coming down with the flu or after riding on the merry-go-round at the park. Another way to be dizzy is to be silly or frivolous: "I can't take him seriously, he's just so dizzy all the time." Dizzy comes from the Old English dysig, "foolish or stupid."