Keep one's nose to the grindstone

From Fresh Dictionary

English

Etymology

First attested 1532, from John Frith's A Mirror to know Thyself:

"This Text holdeth their noses so hard to the grindstone, that it clean disfigureth their faces."

Verb

keep one's nose to the grindstone

1. ((idiomatic{{#if:|, {{{2}}}{{#if:|, {{{3}}}{{#if:|, {{{4}}}{{#if:|, {{{5}}}{{#if:|, {{{6}}}{{#if:|, {{{7}}}{{#if:|, {{{8}}}{{#if:|, {{{9}}}}}}}}}}}}}}}}}}})) to work hard or focus heavily on work

   If he'd keep his nose to the grindstone a bit more, he could be a pretty good student.