Not knowing what is really happening — and so not to blame for it. An unwitting person is caught up in something without understanding it: "an unwitting witness," "the unwitting victim of a scam," "unwitting helpers who thought they were doing charity work." The key idea is innocence through ignorance. You did play a part in it, but you had no idea, so no one can say it was your fault. That is why it appears so often with words like `accomplice`, `victim`, `participant`, `carrier`, and `助手`-type roles: the newspaper is telling you "this person was in the story, but did not know the story." There is a second, quieter use: `unwitting` can describe the act itself rather than the person — "an unwitting insult," "his unwitting mistake." Here it means the person did not mean to do it and did not notice doing it. It is a formal, written word. In everyday speech people say "he had no idea" or "she didn't know." You will read `unwitting` in news reports, court stories, and history books far more often than you will hear it in a café. Almost always it stands in front of a noun (an unwitting fool). Saying "he was unwitting" alone is unusual and sounds odd to most speakers.