curve ball or curve·ball (kûrvbôl′)
1. Baseball Any of several pitches that veer to the left when thrown with the right hand and to the right when thrown with the left hand.
2. Slang Something that is unexpected or designed to trick or deceive: That last question on the exam was a real curve ball.
pitch/throw (someone) a curve ball Slang
1. To mislead; deceive.
2. To cause to be surprised, especially unpleasantly so.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.