tr.v. im·paired, im·pair·ing, im·pairs
To cause to weaken, be damaged, or diminish, as in quality: an injury that impaired my hearing; a severe storm impairing communications.
[Middle English empairen, from Old French empeirer, from Vulgar Latin *impēiōrāre : Latin in-, causative pref.; see IN-2 + Latin pēior, worse; see ped- in the Appendix of Indo-European roots.]
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.