Question

to keep your nose to the grindstone - If you want to pass your exams. You'll just have to keep your nose to the grindstone.  - The new boss is very strict. She certainly keeps everyone's nose to the grindstone.  - At the very least, the pressure I feel has kept my nose to the grindstone for the last month.  - It is highly demoralizing when a subordinate has to keep his nose to the grindstone while the boss just ambles around the office all day shooting the breeze.

Accepted Answer

to keep working hard A grindstone is a stone used for sharpening knives.

Idiom	to keep your nose to the grindstone
Definition	to keep working hard
Examples	- If you want to pass your exams. You'll just have to keep your nose to the grindstone. - The new boss is very strict. She certainly keeps everyone's nose to the grindstone. - At the very least, the pressure I feel has kept my nose to the grindstone for the last month. - It is highly demoralizing when a subordinate has to keep his nose to the grindstone while the boss just ambles around the office all day shooting the breeze.
Note	A grindstone is a stone used for sharpening knives.

Nose Grindstone Boss Working Hard Pass Exams Strict