Ecchi

Ecchi (エッチ), also romanized as etchi, is derived from a Japanese word meaning "erotic", "lewd", "sexy", or "lascivious" when used as an adjective, or sexual intercourse when used as a noun.

Japanese usage
The origin of the term ecchi is uncertain. Ecchi in Japanese is attached to the Japanese pronunciation of the Roman letter "H" which is the first letter in the Japanese word "Hentai", which may be backronym.

The word sekkusu is also used in Japan for sex, and Japanese native words for sex (such as 性交 seikō) are often replaced by words of foreign origin such as sekkusu or neologisms such as ecchi. The nuance of ecchi varies with context, but in general the word itself is comparable to the English words "naughty" or "dirty" (when used as an adjective). The prefix "H-" is sometimes used to refer to pornographic genres: H-anime, H-manga, etc. It is the English-equivalent to "X" for "X-rated" or "XXX".

English usage
In English, the word is often used in the context of manga and anime. The term ecchi is applied to anime or manga that has vague sexual content (such as skimpy clothing, partial or full nudity), but does not show sexual intercourse, making it the manga equivalent of a PG-13 rated movie. Ecchi has historically often been used as a synonym of hentai, presumably due to confusion of the two; thus it can carry different connotations than allowed for by the original Japanese. In recent years, however, its use by English-speakers has largely realigned with the Japanese meaning &mdash; although H has become a completely separate term, inclusive of all of the above.

The ecchi art style is loosely comparable to pin-up girl artwork, as well as to provocative fantasy and comic book art in the United States and other countries. Typical features include:
 * Clothing that outlines the shape of the breasts, nipples, and labia, suggesting tightness of clothing and arousal.
 * Uniforms, costumes, or outfits (all tightly worn) that may be provocative, but are worn as everyday clothing by the character.
 * Bouncing of over-sized breasts, always pointing outwards as if an "invisible bra" was present.
 * The "head in breasts gag," which is commonly used when a male meets a busty female and falls into her cleavage. This can also be known as "Marshmallow Hell".
 * Female characters who look attractive to men, but are unaware of their sexuality, appear innocent and cheerful, or sly and mischievous.
 * The groping of the breasts (whether intentional or not), which ends in either moaning of the girl or a slap on the groper.
 * Clothing that is falling off or being pulled off, notably swimsuits and "sailor"-style schoolgirl uniforms.
 * Upskirt panty shots and cleavage. This is typically known as fan service.
 * Suggestive or explicitly phallic imagery.
 * Exaggerated sexual attributes, often on normal or petite figures to give a sense of contrast. Especially used in dōjinshi and fanart.
 * The occasional bare breast(s) or bottom, but the genital area (such as the cleft of venus) is rarely explicitly shown.
 * Skimpy bathing suits with crotch lines showing and sides of breasts showing.
 * Shining skin indicating sweat or blurry and teary eyes.
 * E.N.F. (Embarrassed nude female): A female character fully/almost nude in public showing signs of embarrassment, humiliation or acting completely normally.
 * The sudden expansion or enlargement of a women's breasts, sometimes with the woman completely unaware.