Trooper is a term that often refers to a military soldier or a state police officer. However, there are several other synonyms for this word that can be used in different contexts. For instance, the term "fighter" can be used as a synonym for a trooper when referring to someone who participates in a battle or conflict. Another synonym could be an "operative," which often refers to someone who carries out a particular mission or task. Furthermore, a "guardian" could also be used as a synonym for a trooper when referring to someone who provides protection or security services. Overall, there are several suitable synonyms for the term "trooper" depending on the relevant context in which it is being used.