limpid

This adjective means clear or transparent. In this context, I have heard it used in relation to water.

In literary contexts it refers to clear writing styles and expression.

It has evolved further to be used in relation to calm, peaceful surroundings.

The Latin source is limpidus meaning ‘clear’ which was absorbed into French and became limpide.

The meaning was retained as it was taken into English in 17 Century as limpid.