Definition of "curveball" [curveball]

• A forespin pitch thrown by rotating the index and middle fingers down and resulting in motion down "curve" (noun)
• An unexpected turn of events initiated by an opponent or chance. (noun)

Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License

• "Not every story has a fairytale ending, of course, but simply being able to move on and move forward after life throws you a curveball is a powerful ability."
• "He can still light up a radar gun with a 95-mph fastball, and his curveball is a "plus" pitch, too."
• "According to Lu, who helped to design a popular Web animation that illustrates the science behind what he calls the curveball illusion, the ball travels relatively straight toward the batter, curving somewhat but not nearly as much as claimed."