To bewilder is to amaze, baffle, dumbfound, flummox, perplex, or stupefy. When you bewilder people, you confuse them.
Bewilder is a fun-sounding word for confusion-causing. A complicated math problem will bewilder many students. A magician's tricks should bewilder the audience. Mystery stories should be a little bewildering, at least until the end. Sometimes, being bewildered has a more emotional element. If someone you know died in a freak accident, that would bewilder you in a very sad way.