"Dutches" is an unusual word, and it's understandable if you're struggling to find synonyms for it. However, there are a few possibilities that might work depending on the context. One option is simply to use the word "duchess" instead, which has the same meaning but is more common. Another option is to use more general terms like "noblewoman," "aristocrat," or "peeress," which can all refer to women of high social status. If you're looking for synonyms that specifically relate to the role of a duchess, you might consider terms like "consort," "spouse," or "partner," depending on the full context of the sentence.