Use accursed to describe something that's under a curse or spell — or just seems like it is. You might call your car accursed if it keeps mysteriously dying in the middle of the road for no apparent reason.
An accursed house might be haunted by a spirit or under an evil spell, or you might describe it as accursed if unexplained things happen in it. You can also use the adjective simply to describe something you're angry about: "This accursed town! I can't wait to move to California!" In the 13th century, the word was acursede, "lying under a curse," from the now-obsolete acursen, "pronounce a curse upon."