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ir·ri·ta·ble (ĭrĭ-tə-bəl)
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adj.
1. Easily irritated or annoyed.
2. Medicine Abnormally or excessively sensitive to a stimulus: irritable bladder.
3. Capable of responding to a stimulus. Used of an organism.
[French irritable, from Latin irrītābilis, from irrītāre, to irritate.]
ir′ri·ta·bili·ty (-bĭlĭ-tē), irri·ta·ble·ness n.
irri·ta·bly adv.
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:

    Indo-European Roots

    Semitic Roots

    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.

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