The anime world has two designations that can sometimes be confusing to newbies. Those are the terms Ecchi and Hentai.

Ecchi (エッチ) is derived from a Japanese word meaning, as an adjective, "lewd", "sexy", "lascivious", or "naughty". It can also mean sexual intercouse when used as a verb or noun.

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.

Typical Ecchi features include:

• Uniforms, costumes, or outfits (all tightly worn) that may be provocative, but are worn as everyday clothing by the character.
• This clothing outlines the shape of the breasts, nipples, and labia, suggesting sometimes arousal.
• Clothing that is falling off or being pulled off, notably swimsuits and "sailor"-style schoolgirl uniforms.
• Skimpy bathing suits with crotch lines showing and sides of breasts showing.
• Upskirt panty shots and cleavage.
• Exaggerated sexual attributes, often on normal or petite figures to give a sense of contrast. Especially used in dōjinshi and fanart, where a character may appear more sexual than normal.
• Bouncing of over-size breasts. The occasional bare breast(s) or bottom can be shown, but not the genital area.
• Suggestive or phallic imagery.
• Characters who are unaware of their sexuality, appear innocent and cheerful, or sly and mischievous.
• E.N.F (Embarrassed Nude Female): A female character fully/almost nude in public showing signs of embarrassment, humiliation or acting completely normally.
• The groping of breasts (whether intentional or not).
• The common gag that is usually pulled off in anime, the "head in breasts gag" that is commonly used when a male meets a busty female and falls into her cleavage.

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.

A fine example of an ecchi anime is Amaenaideyo, Chobits, Elfen Lied and Golden Boy. You can check for more titles here.

Hentai (変態 or へんたい) is a Japanese word that can be used to mean "metamorphosis" or "abnormality". It has a negative connotation and is commonly used to mean "sexually perverted". In the West, is used when referring to sexually explicit or pornographic comics and animation, particularly Japanese anime, manga and computer games.

Hentai anime allow elements of sexual fantasy to be represented in ways that would be impossible to film. This may include portrayals of sexual acts which are physically impossible, unacceptable in society, or run counter to social norms.

The scope of hentai encompasses the entire range of sexual fetishes, including:

• Bakunyū: the depiction of women with large breasts. Literally translated to "bursting breasts"
• BDSM: a spectrum of consensual sexual activities considered to be "kinky" or non mainstream, including such topics as power exchange (domination and submission), bondage, sadomasochism, spanking, etc.
• Bestiality: involving beasts
• Coprophilia: Feces
• Erotic lactation
• Futanari: depictions of hermaphrodites or transsexuals that have both phallic genitalia (penis with scrotum, only a penal shaft, or an enlarged clitoris) and vaginal genitalia or a feminine hourglass shape including breasts and a penis plus scrotum
• Incest: sexual activity between legal familie members
• Lolicon: depicts prepubescent or preadolescent girls
• Maiesiophilia: involving pregnant women
• Omorashi: in which individuals struggle with a full bladder before finally wetting themselves (also known as watersports).
• Shotacon: the depiction of young boys having intercourse, depicting young boys with older women, known as "straight shota" in western jargon.
• Tentacle rape: tentacled creatures and sometimes monsters (fictional imaginative or otherwise, also includes alien-like creatures) engaging in sex or rape with girls and less often men
• Urolagnia: Urinating

You can also divide Hentai into two different main categories: works that feature mainly heterosexual interactions (often abbreviated as "het"), and those that feature mainly homosexual interactions. This second group can be further split into yaoi and yuri subgroups. Yaoi refers to male homosexual pairings, and yuri to female homosexual pairings.

Yaoi commonly features males of ambiguous gender in both physical appearance and mannerism - called bishōnen, which literally means "beautiful boy". Some feature biseinen ("beautiful man"), males of more masculine appearance than bishōnen. Less common are bara - larger, often heavily muscled and sometimes hairy males, the yaoi counterpart of the "bear" in gay pornography - as well as oyaji (meaning "daddy" or "uncle"), featuring middle-aged and elderly men. Yaoi also extends beyond the (sexually explicit) hentai genre, since it is an applies to any anime/manga material that includes male homosexuality. It is, however, distinct from shōnen-ai (literally, "boy-love"), in which two males merely express romantic feelings for each other without actually having sexual relations. Women interested in Yaoi are called "Fujoshi" which means "rotten girl" or "rotten woman".

Yuri is very similar to yaoi, except that the focus is on female homosexual interactions, and the characters in a typical yuri illustration or animation tend to be far less realistic than are the males in yaoi. The characters in yuri are known as "bishōjo" meaning "beautiful girl". Shōjo-ai ("girl love") is a western term for the female equivalent of shōnen-ai.

Here's a link to a list of Hentai shows.

Well, I hope the terms Ecchi and Hentai got a little less confusing. You can say that Ecchi is anime's soft core while Hentai is hardcore!

Ja mata ne! (See you later)