What is the meaning of Grinding?

present participle and gerund of grind

The action of grinding together or crushing into small particles; the sound of this action.

The action of grinding a workpiece to change its size, shape, and surface finish.

A form of dance in which two people rub their bodies together.

Repeatedly performing the same quest or similar in-game activity in order to amass points or wealth.

The act of doing the daily grind.

Of or pertaining to the act or sound of grinding.

Relentlessly taxing; burdensome; exacting to the point of exhaustion.

Crushing; oppressive; overwhelming.

Source: wiktionary.org