What does the word impair mean?

Usage examples for impair

  1. Taxes then, generally, as far as they impair the real capital of the country, diminish the demand for labour, and therefore it is a probable, but not a necessary, nor a peculiar consequence of a tax on wages, that though wages would rise, they would not rise by a sum precisely equal to the tax. – On The Principles of Political Economy, and Taxation by David Ricardo
  2. It will tend also to impair that habit of readiness and quickness which it is necessary to cultivate in order to be agreeable. – The Laws of Etiquette by A Gentleman