Reynard m. Proto-Germanic *ragin 'counsel, might' + Old Saxon hard, Old High German hart 'strong, hard'.
The character of Reynard the Fox was an important one in the medieval literary cycles of France, Germany, the Low Countries, and England, thus contributing to the enduring popularity of the name. The name was so closely associated with foxes that the Middle French form ultimately ended up replacing the native word for 'fox' in French.