n.

1. someone who learned to fight in the streets rather than being formally trained in the sport of boxing;
   street fighter
2. an aggressive and violent young criminal;
   hood, hoodlum, goon, punk, thug, toughie, strong-armer
3. a cruel and brutal fellow;
   bully, hooligan, ruffian, roughneck, rowdy, yob, yobo, yobbo

adj.

1. not given to gentleness or sentimentality
   
   • a tough character
2. very difficult; severely testing stamina or resolution;
   rugged
   
   • a rugged competitive examination
   • the rugged conditions of frontier life
   • the competition was tough
   • it's a tough life
   • it was a tough job
3. physically toughened;
   toughened
   
   • the tough bottoms of his feet
4. substantially made or constructed;
   sturdy
   
   • sturdy steel shelves
   • sturdy canvas
   • a tough all-weather fabric
   • some plastics are as tough as metal
5. violent and lawless;
   ruffianly
   
   • the more ruffianly element
   • tough street gangs
6. feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad');
   bad
   
   • my throat feels bad
   • she felt bad all over
   • he was feeling tough after a restless night
7. resistant to cutting or chewing
8. unfortunate or hard to bear;
   hard
   
   • had hard luck
   • a tough break
9. making great mental demands; hard to comprehend or solve or believe;
   baffling, knotty, problematic, problematical
   
   • a baffling problem
   • I faced the knotty problem of what to have for breakfast
   • a problematic situation at home