impair

verb

im·​pair im-ˈper 

impaired; impairing; impairs

transitive verb

: 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 … sometimes impairing fertility.

—Martha Southgate

impairer noun

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

—Tiffany Sharples

Synonyms

• blemish
• bloody
• break
• compromise
• crab
• cripple
• cross (up)
• damage
• deface
• disfigure
• endamage
• flaw
• harm
• hurt
• injure
• mar
• spoil
• vitiate

Choose the Right Synonym for 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

Examples of impair in a Sentence

Smoking can impair your health.

Drinking impairs a person's ability to think clearly.

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

Recent Examples on the Web

If rain severely impairs your vision, pull over and wait for conditions to improve. —Bay Area Weather Report, The Mercury News, 15 Feb. 2025

According to North Carolina’s Safe Driver Incentive Plan, drivers can see their rates jump by as little as 40% for a moving violation to as much as 340% for driving while impaired or a hit-and-runs resulting in bodily injury or death. —Evan Moore, Charlotte Observer, 14 Feb. 2025

Primary sclerosing cholangitis is when a person's bile ducts become chronically inflamed and scarred, impairing bile transport and fat absorption. —Colleen Doherty, Verywell Health, 13 Feb. 2025

The administration’s early misstep with GCHQ did not impair intelligence exchange or operational cooperation. —David V. Gioe, Foreign Affairs, 13 Feb. 2025

Word History

Etymology

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

First Known Use

14th century, in the meaning defined above

Rhymes for impair

• abwehr
• affair
• affaire
• airfare
• altair
• armchair
• aware
• beware
• bugbear
• carfare
• childcare
• compare

Kids Definition

impair

verb

im·​pair im-ˈpa(ə)r 

-ˈpe(ə)r

: to damage or make worse by or as if by making smaller, less, or weaker

smoking can impair one's health

impairment

-mənt 

noun

Medical Definition

impair

transitive verb

im·​pair im-ˈpa(ə)r, -ˈpe(ə)r 

: 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 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

impairment

-ˈpa(ə)r-mənt 

noun

Legal Definition

impair

transitive verb

im·​pair im-ˈper 

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

impairment noun