To impair something is to make it less effective. If you impair the performance of a car, it will be less able to travel fast or handle difficult terrain.
The oilslickened roads made it difficult for the car to drive smoothly.
The dust and dirt in the air made it difficult for the airplane to fly.
verb
make imperfect
Synonyms:
verb
make worse or less effective
1
These minor scratches can damage the surface of the lens and impair vision.
2
The organ tissue was deeply impaired.
3
A vision disorder is an impairment of the sense of vision.
4
Alcohol may impair your memory.
5
Links to websites impair the credibility of the article.
6
Including children and the disabled such as the visually impaired.
7
She won in the events for the visually impaired.
8
Her cognitive functions were impaired.
9
Her impairment was specific to letters in the alphabet.
10
Fatigue may affect to impaired concentration.