Definitions by Baseball Expert

No-No 

A No-No refers to a perfect game thrown by a pitcher in baseball. NO hits, NO walks. It is commonly misused to refer to a no hitter in which walks were allowed.

Roy Halladay threw a No-No in the 2010 postseason. He is still a loser for being a Philly though.

No-No by Baseball Expert June 1, 2011