curve·ball 
/ˈkɚvˌbɑ:l/ noun
plural curve·balls /ˈkɚvˌbɑ:l/ noun [count] baseball : a pitch that is thrown with spin so that the ball curves in the air
▪ The batter struck out on a curveball. — often used figuratively ▪ Life has thrown him a few curveballs in recent years. [=he has had some difficult and unexpected problems in his life] —called also curve
▪ The batter struck out on a curveball. — often used figuratively ▪ Life has thrown him a few curveballs in recent years. [=he has had some difficult and unexpected problems in his life] —called also curve
