knuckle down

“Being new in town, it was really important to focus and knuckle down,” she said of her decision to focus on acting.

Can we tighten our belts, knuckle down and use that knowledge that our forefathers and mothers gave us?

Meanwhile, put aside all that idea and knuckle down and help.

Sheridan's chief anxiety is for his own interests: 'Knuckle down, and don't funk, Charley.'

That would mean I'd have to knuckle down, and crawl before the mighty Fred Fenton, like some of the other ninnies do.

I should have had to knuckle down very submissively to some ataman, or bully, and this I was not willing to do.

All the same, muttered Bluff, a dozen like him couldnt make me knuckle down, if I knew I was in the right.