The expression All wet means totally wrong or mistaken.

Literally: Completely wet, soaked by a liquid, usually water.

 “I fell in the pool and got all wet.”

For example:

We need to come up with a new ad campaign because, based on these negative reactions, the old one was all wet.

Considering all of our failed experiments, our method must be all wet. What should we be doing differently?

Please, you’re all wet if you think you’ll be able to effect real change in this corrupt city.

You’re all wet if you think Larry is onboard with our plan. He couldn’t care less.

Tradução: estar totalmente equivocado, errado.