Characterized by reaction, especially opposition to progress or liberalism; extremely conservative: The principal is very reactionary; she wants the school to stay the way it has been for the last 50 years.
n. pl. re·ac·tion·ar·ies
An opponent of progress or liberalism; an extreme conservative.
Usage Note: Reactionary means "characterized by reaction, especially opposition to progress or liberalism; extremely conservative." Sometimes reactionary is used to mean "tending to overreact; very reactive," but that sense is widely viewed as a mistake. In 2012, 86 percent of the Usage Panel found the sentence The principal is very reactionary; she responds to every little crisis by calling an emergency meeting to be unacceptable.
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.