Ecchi is a word that has two related but VERY different meanings in Japanese and English respectivly.
English: Ecchi in English speaking anime fandom is considered to mean mildly perverted. It is used to describe anime and manga with panty shots, the occasional nipple, sexual humour, and other forms of fanservice but does not actualy conatain sex.
Japanese: In the Japanese usage "ecchi" literaly means "sex". When the Japanese refer to "ecchi anime" they mean what English speakers would call "hentai", which in Japan is used to mean "pervert"
English: Its not hentai! Its just ecchi!
Japanese: Ano hentai wa ecchi anime ga suki desu.
Translation: That pervert(hentai) likes sex(ecchi) anime.