Deemster is a very unique and unusual word. It is a term used to describe someone who is a judge or jurist in the Isle of Man. However, if you are looking for alternative synonyms to describe a judge or jurist, there are numerous options to choose from. Some of the most common ones include magistrate, justice, adjudicator, arbitrator, arbiter, referee, and assessor. Some less commonly used synonyms might include decider, resolver, wigman, and adjudicant. Regardless of which synonym you choose to use, make sure that it is the most appropriate for the context in which you are using it.