* Disbelieved
* Doubted
* Ignored
* Disregarded
* Scorned
* Contemptuously dismissed
* Indifferent
* Unimpressed
* Skeptical
* Cynical
The best antonym will depend on the specific context of the sentence. For example, if you're talking about someone who was amazed by a magician's trick, "disbelieved" might be a good antonym. But if you're talking about someone who was amazed by a beautiful sunset, "indifferent" might be a better choice.