Definitions of tough:

• noun:   a cruel and brutal fellow
• noun:   someone who learned to fight in the streets rather than being formally trained in the sport of boxing
• noun:   an aggressive and violent young criminal
• adjective:   tough to cut or chew
• adjective:   physically toughened

  Example: "The tough bottoms of his feet"

• adjective:   not given to gentleness or sentimentality

  Example: "A tough character"

• adjective:   violent and lawless

  Example: "Tough street gangs"

• adjective:   feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad')

  Example: "He was feeling tough after a restless night"

• adjective:   substantially made or constructed

  Example: "A tough all-weather fabric"

• adjective:   very difficult; severely testing stamina or resolution

  Example: "The competition was tough"

• adjective:   unfortunate or hard to bear

  Example: "A tough break"