This was a term I came across for the first time a few weeks ago. It means the opposite to déjà vu, (the vivid sense you’ve experienced something before). It is when something happens which seems like it should be familiar, ordinary, but isn’t. It could be a place, a word, a person. You would normally know this instinctively, but it feels like you have heard the word, or being in the place for the first time.