off-the-cuff definition by American Heritage Dictionary
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Not prepared in advance; impromptu: an off-the-cuff remark.
off-the-cuff - Phrases/Idioms
Impromptu, extemporaneous, as in His speech was entirely off the cuff. This term supposedly alludes to the practice of speakers making last-minute notes on the cuff of a shirtsleeve. [1930s]