If you're looking for some alternative words to describe a backstroker, there are a few different options at your disposal. For starters, you could refer to them simply as a backstroke swimmer. Alternatively, you could use the word dorsal swimmer to describe someone who specializes in this particular style of swimming. Another option is backstroke specialist or backstroke expert, which denotes someone who is particularly skilled at this particular swimming technique. Other possibilities might include backstroke champion, backstroke ace, or backstroke pro. Ultimately, the choice of terminology will largely depend on the context in which you are using it, as well as your personal preference and style.