This word was recently pioneered on the radio program Loveline by Adam Carolla.
1. Describes the sound made by a trombone to illustrate a depressing statement, action, or moment. "Wah waah". Pioneered on the SNL skit Debbie Downer.
Bjorn: I don't think so. Nell, would you like to see the pictures I have of Sir Fluffles?
Nell: Oh, Bjorn, I can't bear to look at pictures of cats -- they only make me think of watching my own Mr. Snowflake waste away due to the effects of Feline Leukemia.
Tad: Wow... sad trombone!