Anything exceptionally surprising, unbelievable, outstanding, etc.

“He did? That's a wow!”

To amaze or awe.

“He really wowed the audience.”

An indication of excitement, surprise, astonishment, or pleasure.

An expression of amazement, awe, or admiration.

“Wow! How do they do that?”

Used sarcastically to express disapproval of something.

“Wow... I can't believe you would do such a thing.”