Definitions

1. verb

to drive or cause to go away by or as if by driving away with a sudden movement of the hand, especially with the fingers extended and the palm downward

“She shooed the cat away from the kitchen counter.”

2. interjection

an expression used to urge someone to go away, especially by driving them away with a sudden movement of the hand

“Shoo! Get out of here before the teacher sees you!”

3. noun

a sudden movement of the hand, especially with the fingers extended and the palm downward, used to drive away an animal, especially a bird

“She made a loud shoo at the bird to scare it away.”