What is the meaning of tough?

noun

• Someone who learned to fight in the streets rather than being formally trained in the sport of boxing.
  • synonyms: street fighter
• An aggressive and violent young criminal.
  • synonyms: hood, hoodlum, goon, punk, thug, toughie, strong-armer
• A cruel and brutal fellow.
  • synonyms: bully, hooligan, ruffian, roughneck, rowdy, yob, yobo, yobbo

adjective

• Not given to gentleness or sentimentality.
  • usage: "a tough character"
• Very difficult; severely testing stamina or resolution.
  • usage: "a rugged competitive examination"; "the rugged conditions of frontier life"; "the competition was tough"; "it's a tough life"; "it was a tough job"
  • synonyms: rugged
• Physically toughened.
  • usage: "the tough bottoms of his feet"
  • synonyms: toughened
• Substantially made or constructed.
  • usage: "sturdy steel shelves"; "sturdy canvas"; "a tough all-weather fabric"; "some plastics are as tough as metal"
  • synonyms: sturdy
• Violent and lawless.
  • usage: "the more ruffianly element"; "tough street gangs"
  • synonyms: ruffianly
• Feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad'. )
  • usage: "my throat feels bad"; "she felt bad all over"; "he was feeling tough after a restless night"
  • synonyms: bad
• Resistant to cutting or chewing.
• Unfortunate or hard to bear.
  • usage: "had hard luck"; "a tough break"
  • synonyms: hard
• Making great mental demands; hard to comprehend or solve or believe.
  • usage: "a baffling problem"; "I faced the knotty problem of what to have for breakfast"; "a problematic situation at home"
  • synonyms: baffling, elusive, knotty, problematic, problematical