This is the 2548th most frequent French word.
défi
A challenge.
In this sentence, 'défi' refers to a physically challenging event or task.
Le marathon est un défi physique important.
The marathon is a significant physical challenge.
Here, 'défi' is used to describe a challenge in a professional or career-oriented context.
Accepter les nouveaux projets constitue un défi professionnel.
Taking on new projects constitutes a professional challenge.
In this case, 'défi' indicates a general life challenge or an obstacle to overcome.