Coistril is an interesting word that has a certain ring to it. However, if you're tired of using the same term over and over again, there are some great synonyms that you can use instead. Some good options include words like scallywag, rapscallion, rascal, rogue, devil, miscreant, troublemaker, mischief-maker, and ne'er-do-well. These words all have a slightly different connotation, but they generally refer to someone who is a bit of a troublemaker or someone who doesn't follow the rules. Whether you're writing a story or just looking for a new way to describe someone, these synonyms can help you add some variety to your writing.