Yes, grinds is a Scrabble word!

Verb

1. Press or grind with a crushing noise

2. Make a grating or grinding sound by rubbing together

3. Work hard

4. Dance by rotating the pelvis in an erotically suggestive way, often while in contact with one's partner such that the dancers' legs are interlaced

5. Reduce to small pieces or particles by pounding or abrading

6. Created by grinding

7. Shape or form by grinding

Noun

1. An insignificant student who is ridiculed as being affected or boringly studious

2. The grade of particle fineness to which a substance is ground

3. Hard monotonous routine work

4. The act of grinding to a powder or dust