A patroler is a person who patrols and monitors a given area, whether it's a border, a city street or any other designated location. There are several synonyms for the term "patroler," including "guard," "watchman," "sentinel," "watcher," "sentry," and "patroller." These words all refer to individuals who maintain vigilance in protecting a specific area, often having a specific purpose in mind. For example, a guard may be employed in a store to deter shoplifters, while a sentry is often used to protect military installations. Ultimately, the choice of word used to describe a patroler will depend on the context and setting in which the individual is operating.