What does the word deleterious mean?

Usage examples for deleterious

  1. The horn is often exposed to the vicious influences of unsuitable litter, the application of unsuitable dressings, and the deleterious effects of the street mud of our cities. – Diseases of the Horse's Foot by Harry Caulton Reeks
  2. But the effect on the nerves was deleterious. – The Old Wives' Tale by Arnold Bennett