Other forms: astounding; astounded; astounds
Astound means to amaze. Savants, or those with extreme brain abnormalities, can astound people by their ability to play Beethoven sonatas on the piano after having heard them only once.
Astound has its roots in the verb astonish, originally meaning to stun, and the idea of surprise remains wrapped up in the word. Things like over-the-top fireworks, believable magicians, and the miracle of life tend to astound. But if you lick all your favorite cookies to keep anyone else from taking them––your rudeness could astound as well.