If you have watched the movie, それでもボクはやってない[soredemo boku wa yattenai," Yet, I didn't do that"], you must have heard of this term, 冤罪[enzai]. My dictionary says it means a false accusation, but I think there must be more appropriate word in English, though…
At any rate, this movie is about a man who falsely mischarged as a groper, and it describes how awfully terrible Japan’s court and laws are. No matter how strongly you insist your innocence, even if there’s no evidence which could prove your guilt, you would be charged only if a victim said, “You did it.” Especially in this case, 痴漢冤罪[chikan enzai "false accusation for a groper]. It is said that the possibility you can prove your innocence might be less than 20%. If you get grabbed the wrist by a woman on the train and blamed, there would be nowhere to escape…The more you don’t admit, the longer your custody would be. But if you admit it, they might possibly let you go only if you pay a fine(around 333US$ or so).
Since this controvertial movie came out, this term, 冤罪 is getting more common in public. Actually I knew this term, but I hadn’t heard of it that much. 濡れ衣[nureginu] should be more common. Literally, it means a wet clothes. 濡れ[nure] means wet, and 衣[kinu] means cloth or clothes But how come this means a false accusation as well? There’s two theories to explain how this term came up with;
1. A stepmother who was jealous of her stepdaughter, placed a wet clothes of the fisherman at her pillow while she was sleeping. So her father misunderstood that she slept with the fisherman, and killed her so badly.
2. Wearing a wet clothes, and if the wet clothes dries so fast, you’d be innocent. If not, you’d be guilt. There was a way of judgment a long long time ago.
Incidentally, 免罪[menzai] means acquittal. Compare these two kanji 免 and 冤…see? It made me laugh a bit. There’s something on the top of the kanji, 冤…this is, ワ冠[wa-kanmuri]. And there’s something like a dot around the bottom. It looks as if 冤 was surpressed by ワ冠, and got pinned by the dot so that it couldn’t move. When it comes off, it can be 免(acquittal). This is my theory, so it’s not admissible in court!