The scuba instructor said that the occasional nurse shark might swim near the reef, but it is not an aggressive species. Seeing a shark was improbable, but he said not to panic if we do.
What does the term improbable mean in this context?
In this context, the term "improbable" means that it is unlikely or not very likely for you to see a shark while scuba diving near the reef. Although there is a small chance that a nurse shark might swim nearby, it is not a common occurrence. The scuba instructor is trying to reassure you that encountering a shark is not something you should expect or be overly concerned about.
