1. A cause of fear, anxiety, or irritation: Overcrowding is often a bugbear for train commuters.
2. A difficult or persistent problem: "One of the major bugbears of traditional AI is the difficulty of programming computers to recognize that different but similar objects are instances of the same type of thing" (Jack Copeland).
3. A fearsome imaginary creature, especially one evoked to frighten children.
[Obsolete bug, hobgoblin (from Middle English bugge, perhaps from Welsh bwg) + BEAR2.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.