Not only is the noun that is being referred to totally wack , but it is a wack that is so horrible that you need to add the wiggity infront of the wack. It is has approximately ten times the potentcy of regular type wack. Only to be used in cases where a person is exhibiting extreme stupidity, bitchiness, whining, etc.
"Bill you are acting like you are five years old. I didn't ever think I'd have to say this to anyone...but you are acting completely wiggity wack right now."
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.