What does the word weaken mean?

Usage examples for weaken

  1. " It's a great Game, all right," he said, " if you don't weaken!" – Fairy Prince and Other Stories by Eleanor Hallowell Abbott
  2. These seem to be the great reasons for the study of geometry, and to search for others would tend to weaken the argument. – The Teaching of Geometry by David Eugene Smith
  3. They usually weaken the mind, and sometimes entirely destroy it. – The Young Man's Guide by William A. Alcott