"Arse About" is a slang term that describes a situation where someone is behaving foolishly or in a disorderly manner. If you are looking for alternative words to use instead of "arse about," there are various options to choose from. One option is "goofing off," which can be used to describe someone who is wasting time or being silly. Another synonym is "mucking about," which describes behavior that is senseless or aimless. If you want to emphasize the disorderliness of someone's behavior, you could use the term "chaotic" or "disorganized." Ultimately, there are plenty of words to choose from when describing someone who is "arse about".