To stupefy means to shock or surprise someone to a great degree. When you stupefy someone, they are sometimes left speechless or in a frozen state of shock because they are so amazed by your words or actions. The past tense of stupefy is stupefied.
Ex: John likes stupefying his parents by telling them he is going to become a famous astronaut and create his own planet one day. They never know what to say to his crazy ideas.
The verb stupefy can also be used as adjective. When describe something that is shocking or leaves someone speechless, you can use the word stupefying.
Ex: Cal's speech to the board of directors was stupefying. His ideas were so thoughtful that no one knew how to respond, and the room was silent for the rest of the meeting.
To impress someone means to act in a way that creates respect or shows your strengths or talents. When you impress others, you give them a higher opinion of you than they had before.
Ex: After travelling around the world for three months, Sarah impressed her friends by sharing stories about her adventures and the people she met.
When you leave an impression on someone, you give them a new way of thinking about you. This can be positive or negative. If your behavior is positive, you leave a good impression. But if you act improperly, you leave a bad impression.
Ex: Carl bought flowers and chocolates for his girlfriend's family. He wanted to leave a good impression on them when he met them for the first time.