If I have a non-person object or idea that I consider to be my nemesis1, how could I refer to the object as a noun but use an embellishing adjective to emphasize that the object is my nemesis?
For instance, "Since the end of World War II, Communism has been the [nemesisical] ideology of the United States."
Some words that come to mind include adversarial, opposing, antagonistic, but these don't have quite the same meaning.
1This question was prompted by a non-deleted question on Programmers.SE: Do you have a [programming] language that's your nemesis? (10k only)
