Facultative is an adjective that means related to the granting of permission.

The French word faculte (fa COOLT) refers to a physical or mental power. When the word facultative is used, it is to describe a situation of granting someone power to do something.

Here’s an example:

James gave the film crew permission to shoot their film in the office, but I didn’t know he had that kind of facultative authority. Next time I need permission to do something crazy, I’ll know who to seek permission from.