What does knuckle under mean?

Related questions

1. What does beating around the bush mean?
2. What is high on the hog?
3. What does thinking on your feet mean?
4. Does cracking your knuckles harm you?
5. Is it bad to crack your back everyday?
6. What does the idiom beat around the bush means?
7. What is the space between your knuckles called?
8. Do your knuckles get bigger when you crack them?
9. Do knuckles get bigger when you crack them?
10. What are foot knuckles called?

Tags

1. #knuckles
2. #violence
3. #kneeling
4. #students
5. #demands
6. #position
7. #alludes
8. #their
9. #refused
10. #presumably
11. #idiom
12. #threats
13. #acknowledge
14. #hands
15. #knuckle
16. #graduate
17. #ground
18. #under
19. #forced
20. #defeat
21. #before