tough

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Able to withstand great strain without tearing or breaking; strong and resilient: a tough all-weather fabric.
2. adj. Hard to cut or chew: tough meat.
3. adj. Physically hardy; rugged: tough mountaineers; a tough cop.
4. adj. Severe; harsh: a tough winter.
5. adj. Aggressive; pugnacious.
6. adj. Inclined to violent or disruptive behavior; rowdy or rough: a tough street group.
7. adj. Demanding or troubling; difficult: skipping the toughest questions.
8. adj. Strong-minded; resolute: a tough negotiator.
9. adj. Slang Unfortunate; too bad: a tough break.
10. adj. Slang Fine; great.
11. n. A violent or rowdy person; a hoodlum or thug.
12. idiom. tough it out Slang To get through despite hardship; endure: "It helps if one was raised to tough it out” ( Gail Sheehy).

Century Dictionary and Cyclopedia

1. Having the property of flexibility without brittleness; yielding to a bending force without breaking; also, hard to cut or sever, as with a cutting-instrument: as, tough meat.
2. Firm; strong; able to endure hardship, hard work, or ill usage; hardy; not easily broken or impaired.
3. Not easily separated; tenacious; stiff; ropy; viscous: as, a tough clay; tough phlegm.
4. Not easily influenced; unyielding; stubborn; hardened; incorrigible.
5. Hard to manage or accomplish; difficult; trying; requiring great or continued effort.
6. Severe; violent: as, a tough rebuke or tirade; a tough storm.
7. n. A rough; a bully; an incorrigibly vicious fellow; a bad character.

Wiktionary

1. adj. strong and resilient; sturdy
2. adj. difficult to cut or chew
3. adj. rugged or physically hardy
4. adj. Stubborn.
5. adj. harsh or severe
6. adj. rowdy or rough.
7. adj. difficult or demanding
8. adj. Undergoing plastic deformation before breaking.
9. interj. Used to indicate lack of sympathy
10. n. A person who obtains things by force; a thug or bully.
11. v. To endure.
12. v. To toughen.

GNU Webster's 1913

1. adj. Having the quality of flexibility without brittleness; yielding to force without breaking; capable of resisting great strain.
2. adj. Not easily broken; able to endure hardship; firm; strong; -- of objects and people.
3. adj. Not easily separated; viscous; clammy; tenacious.
4. adj. Stiff; rigid; not flexible; stubborn.
5. adj. Severe; violent.
6. adj. Difficult to do, perform, or accomplish.
7. adj. Prone to aggressive or violent behavior; rowdyish; -- of people, or groups.
8. n. A person who is tough{7}; a ruffian; a thug.

WordNet 3.0

1. adj. making great mental demands; hard to comprehend or solve or believe
2. n. an aggressive and violent young criminal
3. n. someone who learned to fight in the streets rather than being formally trained in the sport of boxing
4. adj. unfortunate or hard to bear
5. adj. substantially made or constructed
6. adj. physically toughened
7. n. a cruel and brutal fellow
8. adj. very difficult; severely testing stamina or resolution
9. adj. feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad')
10. adj. violent and lawless
11. adj. not given to gentleness or sentimentality
12. adj. resistant to cutting or chewing