knuckle

/ˈnʌkəl/

• Noun
• any one of the thick, bony parts (called joints) in your fingers
1. She rapped her knuckles on the table.
• a piece of meat that includes a joint from the leg of an animal
1. a pork knuckle
• Verb
• to begin to work hard
1. It's time to knuckle down and get to work.
2. She knuckled down to the task.

• to stop trying to fight or resist something
1. Despite the pressure, he refused to knuckle under. [=give in]
2. He refused to knuckle under to anyone.
3. He finally knuckled under to the pressure.