Pellucid
/pəˈluː.sɪd/ adjective hardSomething pellucid is so transparent or plainly expressed that it can be understood or seen through without any effort.
The professor's pellucid explanation of the tax code made a notoriously confusing subject feel simple.
Memory Trick
Pellucid contains 'lucid' - just add extra clarity to get something even more crystal clear than lucid alone.