Stun. To render unconscious, to shock or surprise.
You are stunned if you hit your head and lose consciousness.
Stun is used to express great surprise or shock. I was stunned when I found out I'd won the football pools (I wish! It's only an example :-)
Stun has been popularised as the adjective "stunning". Stunning means very attractive, impressive, astonishing.
Like a beautiful and vivid photograph.
Or a brilliant theatrical performance.
Advertising copy likes the word too. Your hairdresser offers you a stunning new look, and property developers promise you a stunning new home (see photo). But then, they are only words :-)