Astound can be used as given below examples,
I was astounded by all his knowledge and talent.
Everyone was astound by his the performance in dance show.
Adjective astound: to be amazed, astonished
Verb: shock with surprise or wonder, bewilder
To be impressed unexpectedly
Astound has synonyms like amaze, astonish, surprise, shock, overwhelm
Use this word ‘Astound’ on English Chats while Chatting or while posting an article on Express English or while talking to your friends.