It is a lubricant. There's a lot of confusion around this because it often isn't a great lubricant for the purposes it gets used for, like door hinges or bicycle parts. But it most definitely is a lubricant.

https://www.wd40.com/myths-legends-fun-facts/

Water displacer, hence the name, right?

It's a mixture of light mineral spirits and mineral oil.

Oil displaces water, who knew?