ecchi

The story

1. English · derived fromaitch“name of the letter ⟨H⟩”
2. Japanese · borrowed fromエッチ“dirty; perverted”
3. English todayecchi

From Japanese エッチ (etchi, “dirty; perverted”), which is derived from English aitch (“name of the letter ⟨H⟩”), which is an initialism of the romaji of Japanese 変(へん)態(たい) (hentai, “pervert”). エッチ (etchi) is not a genre in Japanese; this is a development in English (pseudo-Japonism), similar to that of hentai from 変(へん)態(たい) (hentai, “pervert”) above.