MOST DOMESTICATED can be described as the tamest, which is a 6-letter word. Tamest means to be the least wild or ferocious, and is often used to describe animals that have been domesticated by humans. Domestication is the process of adapting wild animals to live in close association with humans, and is usually done through selective breeding. Therefore, MOST DOMESTICATED would refer to animals that have been domesticated for the longest period of time and are the least wild or ferocious.