1. small, loose particles of stone or sand.
“she had a bit of grit in her eye”
2. courage and resolve; strength of character.
“he displayed the true grit of the navy pilot”
1. clench (the teeth), especially in order to keep one’s resolve when faced with an unpleasant or painful duty.
“Congress must grit its teeth and take action”
2. move with or make a grating sound.
Take your pick.