grit

noun

1. rough, hard particles of sand, stone, etc.
2. the texture of stone, with regard to the fineness or coarseness of its grain
3. any of several sandstones with large, sharp grains, often used for grindstones
4. ☆ stubborn courage; brave perseverance; pluck

transitive verb gritted, gritting

1. to cover with grit
2. ☆ to clench or grind (the teeth) in anger or determination

intransitive verb