What's the difference between a smack and a slap?

Answer: A smack is when you hit someone directly (like the palm of your hand just hits them dead-on)

A slap is when you hit someone and your hand is kind of directed to the side so it either moves the object to the side or slides off of the object in a sideways manner

Explanation:

Just how I imagine it.

Answer: a smack is when someone does a slap but super hard. A slap is a light attack to the face that still hurts just not as bad.