When events have been building toward a high point — a story, a sports final, a big reveal — and then what happens is weak, small, or oddly ordinary, so the air goes out of the room. You were ready to feel a lot, and the ending does not earn it. “The last episode was an anticlimax” is a very common complaint. Though actually, climax here is the peak of a story or event. English also uses climax for a sexual peak, but anticlimax in ordinary talk is almost always the disappointing-ending meaning, not the bedroom one. It is not about climate or weather, even though the letters can look a little like “anti-climate” if you read too fast.

反高潮