The word "sorriest" is often used to express extreme regret or apology. However, there are several synonyms that can be used interchangeably to convey a similar meaning. One such synonym is "regretful", which implies a feeling of sorrow or remorse. "Apologetic" is another suitable replacement, indicating a sincere expression of apology. Additionally, the term "contrite" can be used to reflect a deep sense of guilt or remorse for one's actions. "Remorseful" is a synonym that expresses the feeling of deep regret for a past mistake. Lastly, "repentant" conveys a sense of sorrow and a desire to make amends. All these synonyms capture the essence of "sorriest" and can be employed to express similar sentiments.