Here is a good example sentence (that I made up, as an example of an example sentence):
Michael Brown was prepared for his job as a sinecure, not his job as a cynosure.
I wondered why both of those words aren't in the usual "frequently confused words" lists. Then I realized, first, that they are and second, that if you know two such mildly obscure words well enough to risk using one of them, you probably have a pretty good vocabulary already, so the typical "frequently confused words" lists wouldn't apply to you. But it applies to me, because I think I pronounced sinecure more like cynosure once, but I didn't know what cynosure meant until today. It comes from the name of the main star of the big dipper, the north star. So I should have known it, but I will just be glad I know it now.