from The American Heritage® Dictionary of the English Language, 5th Edition.

  • transitive verb To cause to weaken, be damaged, or diminish, as in quality.

from The Century Dictionary.

  • noun Diminution; decrease; loss; injury; disgrace.
  • Not one of a pair; odd; unmatched.
  • noun An impaired or odd thing; an article without a mate.
  • noun In roulette, an odd number.
  • To make worse; diminish in quantity, value, excellence, strength, or any other desirable quality; deteriorate; weaken; enfeeble: as, to impair the health or character; to impair one's fortune.
  • Synonyms To lessen, decrease, reduce, injure.
  • To become worse; be lessened or enfeebled; deteriorate.
  • Unequal; unworthy; unjust.

from the GNU version of the Collaborative International Dictionary of English.

  • adjective obsolete Not fit or appropriate.
  • transitive verb To grow worse; to deteriorate.
  • noun obsolete Diminution; injury.
  • transitive verb To make worse; to diminish in quantity, value, excellence, or strength; to deteriorate.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • verb to weaken; to affect negatively; to have a diminishing effect on.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • verb make worse or less effective
  • verb make imperfect


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English empairen, from Old French empeirer, from Vulgar Latin *impēiōrāre : Latin in-, causative pref.; see in– + Latin pēior, worse; see ped- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Old French empeirier, from Vulgar Latin *impeiorare, from in- + Late Latin peiorare ("to make worse"), from peior ("worse"), a comparative of malus ("bad").


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  • Limits on expression impair the Chinese quality of life, mutes the ability of its political economy to secure progress, and can allow legitimate grievances to fester until they get out of control.

    Wash Park Prophet 2009

  • The order says that states may not "impair" or even "condition" a national bank's ability to exercise its powers.

    What Big Banks Fear More Than the CFPA 2010

  • The order says that states may not "impair" or even "condition" a national bank's ability to exercise its powers.

    Stacy Mitchell: What Big Banks Fear More Than the CFPA 2010

  • We will ignore those requirements when we conclude that it will "impair" what occurs in the Executive branch.

    Balkinization 2006

  • Without the bankruptcy financing, the remaining critical employees will likely depart, which would "impair" WorldSpace's ability to operate the satellites and continue as a going concern, Samara said.

    WorldSpace Files for Bankruptcy, Listing $2.12 Billion in Debt 2008

  • Clicking through this EULA appears to allow Pinnacle to install software automatically from third parties onto your computer – software which the vendor admits may "impair" the program ( "the Software") you have just purchased, as well as "any other software on your computer which specifically depends on the Software."

    - Boing Boing 2005

  • It may kind of impair it, as well as your motor skills.

    CNN Transcript Oct 21, 2006 2006

  • If the work made for hire clause were to be retroactively corrected so that it did not automatically give the commissioning party such an interest, regardless of contractual language that was intended to make such a transfer, it would "impair" the contracts that depend upon those clauses.

    Scrivener's Error 2003

  • Should such a sum be issued it would be followed by a great "impair", if not utter loss of the public credit.

    Currency and Banking in the Province of the Massachusetts-Bay [excerpts] 1901

  • Still farther: If Congress be allowed to imply this power (as to a legal tender), it gains, by the political ledgerdemain of construction, the power not merely to "impair," but to violate and extinguish the obligation of contracts!

    "Cato" on constitutional "money" and legal tender. In twelve numbers from the Charleston Mercury. 1862


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  • "Basic services -- electricity, water, food -- were terribly impaired and the economy, in the process of being privatized by the neocon overseers of the occupation, was simply wrecked."

    - Tom Engelhardt, Biking Out of Iraq,, 13 August 2009.

    August 14, 2009