The word "strengthiest" is not a widely recognized term. Therefore, it is important to consider the varying ways to express strength in the English language. Some synonyms for strengthiest are strongest, mightiest, most powerful, most robust, most vigorous, and toughest. Depending on the particular context, one can use any of these words to convey the idea of having a significant amount of physical or mental strength. The word "strengthiest" may not be the most appropriate term to use in most cases, but having knowledge of its synonyms can help individuals to communicate effectively in a variety of situations.