1: more than amazing but less than crazy 2:sarcastically emphasizing amazing to make fun of someone (for example: someone who works really hard on something and is then surprised that they Aced it)
1 and 2:
person 1: WOW! i got a 100 on my algebra test! i can't believe it! this is amazizing......
person 2: wow that is amazizing...*cough* *not* then again you did study all night... you deserved it! now stop rubbing your great grade in my face or i swear to god i'll punch you
one more "zi" than just amazing, sometimes used when something is better than something else and one is trying to top another thing
Bob: Fergie is soooooooooooooo amazing!
Jack: HEY! She's hotter than that! She's amazizing!