What does the word tough mean?

Usage examples for tough

  1. The stem is tough, solid, whitish. – Studies of American Fungi. Mushrooms, Edible, Poisonous, etc. by George Francis Atkinson
  2. No need to get so tough. – Danger at the Drawbridge by Mildred A. Wirt
  3. After a few minutes he came down and said to me, 'That fellow's a tough proposition. – Tales of the Road by Charles N. Crewdson