grind

grind is a Verb

Definition:

[1] To reduce to powder by friction, as in a mill, or with the teeth; to crush into small fragments; to produce as by the action of millstones. Take the millstones, and grind meal. Is. xivii. 2.

[2] To wear down, polish, or sharpen, by friction; to make smooth, sharp, or pointed; to whet, as a knife or drill; to rub against one another, as teeth, etc.

[3] To oppress by severe exactions; to harass. To grind the subject or defraud the prince. Dryden.

[4] To study hard for examination. [College Slang]