Ecchi (エッチ, etchi?, ) is an often used slang term in the Japanese language for erotic fantasy and sexual innuendoes. As an adjective it is used with the meaning of "dirty", "naughty", "frivolous"; as a verb (ecchi suru), with the meaning to do something dirty, naughty, frivolous or to sleep together; or as a noun, to describe someone that is seen as ecchi. It is a synonym for ero (from Eros) and does not have such a harsh meaning as hentai.
The word is not only common in Japan, it is also used worldwide inside the fandom of Japanese media to describe sexual themes or undertones. While the word ecchi could mean anything from mild to insulting in Japanese language, it is used in Western culture to divide between pornography (hentai) and playful usage of sexualized imagery (ecchi). Works considered as ecchi do not show any sexual intercourse or primary sexual characteristics. Instead, it is up to the imagination of the viewer. Inside such media, it often goes along with fan service in a humorous way. These kinds of sexual themes or undertones can usually be found in comedic Shōnen/Seinen manga and harem anime.