"No-no" is an abbreviation for a baseball no-hitter
a game in which a pitcher
does not allow a single base hit
in nine or more innings
Example: "And with that latest strikeout, Nolan Ryan has a no-no through six!"
The term was coined by former Pittsburgh Pirates pitcher Dock Ellis during his LSD-induced no-hitter in 1970. While his team was hitting in the seventh inning, he told second baseman Dave Cash, "Hey, look, I've got a no-no going!"