The antonym of "most stained" can vary depending on the context. However, some of the possible antonyms of "most stained" are "cleanest," "spotless," "unsullied," "unblemished," "pure," "immaculate," "untarnished," "flawless," "undefiled," "wholesome," among others. These antonyms describe an object or a surface that is free from any stain, discoloration, or dirt. They signify a high level of cleanliness and purity, which is the opposite of "most stained." Antonyms are important in language and help to understand the full picture by providing a complete contrast to words that are being used in a particular situation.