What does TOUGH mean?

adjective

1. not given to gentleness or sentimentality“a tough character”
2. very difficult; severely testing stamina or resolution“a rugged competitive examination”
3. physically toughened“the tough bottoms of his feet”
4. substantially made or constructed“sturdy steel shelves”
5. violent and lawless“the more ruffianly element”
6. feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad')“my throat feels bad”
7. resistant to cutting or chewing
8. unfortunate or hard to bear“had hard luck”