Hentai is a Japanese word that, in the West, is used when referring to sexually explicit or porn comics and animation, particularly those of Japanese origin such as anime, manga and games. The word “hentai” has bad notation in Japan and is usually used as “sexually perverted”.
In Japanese the word hentai is a kanji. The term is used as a shortened form of the phrase (hentai seiyoku), or “sexual perversion”. In slang, hentai is used as an insult meaning roughly “pervert” or “weirdo”. The term is not often applied to pornography in Japan.