1. A conceited or impudent person.
2. A mischievous child.
3. Archaic A monkey or an ape.
[From Middle English Jack Napis, nickname of William de la Pole, Fourth Earl and First Duke of Suffolk (1396-1450), probably ultimately from alteration of ape, monkey, ape (because his coat of arms depicted a chain and clog of the kind used to tether a pet monkey).]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.