* Fair/Light: Very pale skin that burns easily in the sun.
* Medium: A moderate skin tone that tans more easily than fair skin.
* Olive: A slightly tanned skin tone.
* Tan/Brown: A darker skin tone that tans easily.
* Dark Brown/Black: Deeply pigmented skin.
These descriptions, combined with qualifiers like "cool," "warm," or "neutral" undertones, are used to describe skin color more accurately.
It's possible someone might use "indigo" poetically or metaphorically to describe skin with a very dark, almost bluish undertone, but this would be highly unusual and not a standard way to classify skin color. Skin can appear to have a bluish tint in certain conditions like cyanosis, but this is a medical issue rather than a natural skin tone.