1. Having in the head a sensation of whirling or reeling about; having lost the power of preserving the balance of the body, and therefore wavering and inclined to fall; lightheaded; dizzy.
2. Promoting or inducing giddiness.
3. Over-excited; mirthful.

1. To make giddy
2. To become giddy

A command (as to a horse) to go ahead or go faster.