1. A phrase you say when you want to get somebody's hopes
up.

2. A phrase you say when somebody says something
unlikely or unrealistic.
1. Ben: I hope somebody hands in my wallet.
Steve: Ah, not happening!

2. Bob: On my 21st birthday, Britney Spears and Madonna
are coming to my party.
Philip: Ah, not happening!

by Savona December 21, 2006
Get the ah, not happening mug.