originala

Two senses, and Esperanto keeps both: not copied from anywhere, and not translated from anywhere. The second is a live distinction in Esperanto publishing, where a work is either originala or tradukita and the label matters to readers.

The trap is the English sense that does not carry. When you mean original in the sense of first or earliest, use unua or komenca instead. La originala plano says the plan was inventive; la unua plano says it was the one before the current one. The noun form originalo is the original object or text itself.