Clear is not found on the color wheel, and is not a specific color. It is used to describe the absence of darkness or opacity in a color.
Clear refers to a lack of darkness or darkening elements in a color, or to the degree to which light remains pure and uncolored. As such, clearness does not so much define a specific color as a relative lack of chromatic elements in a perceived color. It also denotes translucence or transparency in a given substance. The use of "clear" as a verb synonymous with "rid" or "empty" further points to the essential suggestion of an absence or void, rather than a presence, even that of a color, when clear is used as an adjective or adverb.