Something ingenious shows creativity and inventiveness. If someone compares you to Einstein, they're implying that you, too, are ingenious.
Ingenious comes from the Latin words for inborn talent. It started off meaning someone who was talented or incredibly smart, but has come to mean inventive, or clever. If you can solve 146,392 * 27,453 in your head, people might call you a math genius. But if you come up with a way to turn water into fuel, you will be praised as ingenious. Ingenious can also describe thing, like an ingenious device.