grind 
(grīnd)
(grīnd)v. ground (ground), grind·ing, grinds
v.tr.
1.
a. To reduce to small bits or crush to a fine powder: grind wheat into flour; grind coffee beans.
b. To shape, sharpen, or refine with friction: grind scissors to a fine edge; grind lenses for eyeglasses.
2. To rub (two surfaces) together harshly; gnash: grind one's teeth.
3. To bear down on harshly; crush: The team's spirit was ground down by harsh losses.
4. To oppress or weaken gradually or persistently: "Laws grind the poor, and rich men rule the law" (Oliver Goldsmith).
5. To operate by turning a crank: ground a hurdy-gurdy.
6. To instill or teach by persistent repetition: ground the truth into their heads.
v.intr.
1. To perform the operation of grinding something.
2. To become crushed, pulverized, or powdered by friction: Those coffee beans ground easily.
3.
a. To move with noisy friction; grate: a train grinding along rusty rails.
b. To ride a skateboard, a snowboard, or skis over a grind rail or narrow surface, often with the board or skis at right angles to the direction of movement.
4. Informal To devote oneself to study or work: grinding for a test; grinding away at housework.
5. Slang To rotate the pelvis erotically, as while dancing or performing a striptease.
n.
Phrasal Verb: 1. The act of grinding.
2. A crunching or grinding noise.
3.
a. A specific grade or degree of pulverization, as of coffee beans: drip grind.
b. Bits of ground coffee; grounds.
4. Informal A laborious task, routine, or study: the daily grind.
5. Informal A student who works or studies excessively.
6. Slang An erotic rotation of the pelvis.
grind out
Idiom: To produce mechanically or without inspiration: a hack writer who grinds out one potboiler after another.
grind it out
To make a persistent effort in doing something that is difficult; work at something persistently.
[Middle English grinden, from Old English grindan; see ghrendh- in the Appendix of Indo-European roots.]
grinding·ly adv.