verb im·pair \ im-ˈper \
|Updated on: 6 Jul 2018

Definition of impair

impaired; impairing; impairs
: to diminish in function, ability, or quality : to weaken or make worse
  • It has been known for nearly 100 years that memory is impaired by bilateral damage to either of two brain regions …
  • —Larry R. Squire
  • The use of drugs further complicates the situation of these families and sometimes impairs their ability to raise children.
  • —Ellen L. Bassuk
  • … the prospect of generating normal profitability is impaired by excessive debt service.
  • —John Nozell
  • The physician also checks for signs of endometriosis, a condition in which the cells that normally compose the uterine lining grow outside the uterus, sometimes impairing fertility.
  • —Martha Southgate


    • … the overwhelming majority of hookups involved alcohol use—an impairer of sexual judgment if ever there was one …
    • —Tiffany Sharples


play \im-ˈper-mənt\ noun
    • Persons with hearing impairments can now get information about local parks and their facilities by calling the recently installed TDD phone numbers within the Parks Department.
    • Maryland Magazine

Examples of impair in a Sentence

  1. Smoking can impair your health.

  2. Drinking impairs a person's ability to think clearly.

  3. His memory was so impaired by age that he often forgot where he was.

Recent Examples of impair from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'impair.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of impair

Middle English empeiren, from Anglo-French empeirer, from Vulgar Latin *impejorare, from Latin in- + Late Latin pejorare to make worse — more at pejorative

Synonym Discussion of impair

injure, harm, hurt, damage, impair, mar mean to affect injuriously. injure implies the inflicting of anything detrimental to one's looks, comfort, health, or success.
    • badly injured in an accident
harm often stresses the inflicting of pain, suffering, or loss.
    • careful not to harm the animals
hurt implies inflicting a wound to the body or to the feelings.
    • hurt by their callous remarks
damage suggests injury that lowers value or impairs usefulness.
    • a table damaged in shipping
impair suggests a making less complete or efficient by deterioration or diminution.
    • years of smoking had impaired his health
mar applies to injury that spoils perfection (as of a surface) or causes disfigurement.
    • the text is marred by many typos

Financial Definition of IMPAIR


What It Is

The term impairment refers to assets that are no longer of the same value as in a prior period. An impairment charge is used and the asset is revalued downward and a "charge" is made to net assets.

How It Works

Impairment normally happens when the value of a company's goodwill declines in market value. Since the advent of FAS (Financial Accounting Standards) 141 and 142, the amortization of goodwill is no longer required, however periodic and annual impairment tests are now necessary. This can work both ways. The goodwill (asset) will stay on the books of the company indefinitely which helps EPS but if there is a market downturn on these assets, a write-down of the value of the asset (impairment charge) will be required which has immediate impact on the income of the company.

For example;

Goodwill Asset  Value (Year 0) $4,000,000

Impairment Test Results Value (Year 1) $3,000,000

Income Statement Impact/ Impairment Charge $1,000,000

Why It Matters

Under US GAAP (Generally Accepted Accounting Principles), tests of impairment are required annually. Thus, an internal control procedure must be established within companies that potentially have such exposure to ensure they are abiding by US GAAP. Failure to do so risks a qualified or adverse opinion from the companies’ auditors.

IMPAIR Defined for Kids


verb im·pair \ im-ˈper \

Definition of impair for Students

impaired; impairing
: to make less (as in quantity, value, or strength) or worse : damage Smoking can impair your health.

Medical Dictionary


transitive verb im·pair \ im-ˈpa(ə)r, -ˈpe(ə)r \

medical Definition of impair

: to damage or make worse by or as if by diminishing in some material respect
  • his health was impaired by overwork


play \-ˈpa(ə)r-mənt\ noun

Law Dictionary


transitive verb im·pair \ im-ˈper \

legal Definition of impair

1 : to damage or make worse by or as if by diminishing
  • impaired health
2 : to diminish the value of (property or property rights); specifically : to diminish the value of (legal contractual obligations) to the point that a party loses the benefit of the contract or the contract otherwise becomes invalid
  • a law impairing a state's own obligations was entitled to less deference
  • —Gerald Gunther
— see also contract clause



Seen and Heard

What made you want to look up impair? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!


a downward inclination or slope

Get Word of the Day daily email!

Test Your Vocabulary

Obscure Shapes

  • a-pile-of-three-dimensional-shapes-in-green
  • Something that is ooid is shaped like:
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!