tooth
The French word for 'tooth' is 'dent'. It is a feminine noun in French. For example, 'une dent' means 'a tooth'. It's used in many common phrases such as 'brosse à dents' which translates to 'toothbrush'.
I brush my teeth every day.
In French, 'dents' is the plural of 'dent' meaning teeth. This sentence illustrates one's daily hygiene habit of brushing teeth.
I have a toothache.
'J'ai mal à la dent' is a common phrase used in French to express that one is experiencing tooth pain. 'Mal' means pain, 'à la' is a contraction of 'à' + 'la', and 'dent' means tooth.
He has a grudge against me.
The phrase 'Il a une dent contre moi' is a French idiomatic expression. Despite the direct translation to English being 'He has a tooth against me', it means 'He has a grudge against me' or 'He bears a grudge against me'.