Why do people call a toilet the khasi?

There seems to be a misunderstanding. "Khasi" is not a common term for a toilet in any language.

It's possible you are thinking of:

* "Crapper," a slang term for a toilet, derived from the name of the inventor, Thomas Crapper.

* "Potty," a child's word for a toilet, often used playfully.

* A specific regional slang term for a toilet, unique to a certain area.

Could you please provide more context or clarify what you are referring to?