GIDDIEST

Dizzy, feeling dizzy or unsteady and as if about to fall down.

"The man became giddy upon standing up so fast."

Causing dizziness: causing dizziness or a feeling of unsteadiness.

"They climbed to a giddy height."

Lightheartedly silly, or joyfully elated.

"The boy was giddy when he opened his birthday presents."