Implied topless involves the model being topless in the image, but hiding the nipples with posing, lighting and/or props.
Implied nudity involves the model being nude in the image, but hiding the more sensitive parts of the body including the nipples and genitals with posing, lighting and/or props.
Implied nudity is my specialty, and is the style I focus on the most nowadays.
Artistic Topless fully exposes the breasts and nipples, but hides the lower genitals by strategic framing or using a piece of clothing for the lower half of the body.
Artistic nude shows the full body nude in a tasteful, artistic way.