grit2 [transitive] past tense and past participle gritted, present participle gritting
to scatter grit on a frozen road to make it less slippery
to use all your determination to continue in spite of difficulties:
Just grit your teeth and hang on - it'll be over soon.
to bite your teeth together, especially when you are in pain, angry, or under pressure:
Ben gritted his teeth, hoping Sasha wouldn't notice his fear.
'No, that's alright,' she said through gritted teeth.