Translated literally, avoir une dent contre means ‘to have a tooth against’.
What does this have to do with a humanitarian mission in Africa?
French humanitarian Claude Cazes, from Hérault, embarked on a mission at the end of March walking from Burundi to Egypt, distributing medicines to five NGOs along the way.
Mr Cazes was almost at the end of his 6,000km journey when Egyptian authorities stopped him and placed him in a hotel under police surveillance.
After a few days, Mr Cazes took to Facebook to call for action from the French authorities in Egypt.
He said: “I’m trapped in a hotel for no reason because the embassy and the consulate are shifting the blame between each other. Wake up! Do your jobs!”
Since posting his message, Mr Cazes has been given authorisation to fly to France on August 13. He does not blame the Egyptian authorities for his experience, but continues to avoir une dent contre – feel angry or resentful towards – the French authorities.
This expression dating from the 14th century evolved from avoir les dents sur quelqu’un – to have your teeth on someone.
As there were no dentists in the modern sense in the 14th century, just ‘tooth pullers’, teeth at the time were commonly associated with pain.
But in this expression, they are a symbol of aggression. After all, if you have your teeth on someone it is quite possible that you’ve just bitten them.
Some sources also say the expression may also be linked to the idea of animals ‘showing their teeth’ when they are in an aggressive mood.
By the 17th century, the expression had evolved to just une dent, one tooth, though it is unclear why.
One variant found in Molière, but not used today, was avoir une dent de lait (a young child’s ‘baby’ tooth) contre quelqu’un to refer to a longstanding grudge