To hit someone or something with the open hand, making a loud noise.
Slapping can be a sign of anger or disrespect.
Examples:
She slapped the table and it made a loud noise.
He slapped the ball with his hand.
The cat slapped the mouse with its paw.
I slapped the water and it splashed everywhere!
He slapped the fly and it flew away quickly.
The wind slapped my face as I walked outside.