"Play by ear" is a phrase often used to describe someone who is able to improvise or perform without following a set plan. If you are looking for synonyms for "play by ear," there are a few options to consider. One alternative phrase might be "wing it," which means to proceed without preparation or a clear plan. Another option could be "improvise," which means to create or perform on the spot without a script. Lastly, "ad lib" is another term that could be used to describe playing by ear, as it means to improvise or make up as you go along.