Astonishment is what you feel when you're extremely surprised. If a cat stood up and recited the Preamble to the Constitution, you’d stare in astonishment.
Astonishment is the feeling of being blown away and shocked by something. It’s the noun form of astonish, which is a verb meaning, basically “to have your mind blown.” A professional magician aims to create astonishment. A basketball player who hits every three-point shot might make fans feel astonishment. Many people feel astonishment when looking at something like the Grand Canyon. This is a strong word that shouldn't refer to minor surprises. True astonishment is rare.