a. One who tells or plays jokes.
b. An insolent person who seeks to make a show of cleverness.
c. Informal An annoying or inept person: Some joker is blocking my driveway.
2. Games A playing card, usually printed with a picture of a jester, used in certain games as the highest-ranking card or as a wild card.
3. A clause that is included in a legislative bill or a contract in order to render the bill or contract inoperative or oppressive in some respect while appearing to be innocuous until the harm has been done.
4. An unforeseen but important difficulty, fact, or circumstance.
5. A deceptive means of getting the better of someone.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.