"bathroom", "restroom" "loo" "WC"....all euphemisms. A park near me once had a sign saying "Comfort Station". The only one that strikes me as 'clear' is "toilet", and that really refers to the fixture.

It is fascinating how firmly we cling to the locutions we heard in childhood, or phrases uttered by 'famous' people, and how we rebel when changes come about.

   I know of both British and American usages I would rather see replaced by something less obtuse and colloquial.