Go to your county’s website and look up restraining orders. There are civil and criminal ROs, and they’re based on different complaints, but a “no contact” order means no contact.
You may even be able to download the forms and see what filling them out feels like. They can seem incredibly invasive and can call for supplying detailed documentation. Whatever you put on those forms you may also have to say aloud before a judge in a courtroom, explaining in compelling detail exactly why you require the protection of the law.
My advice would be to exhaust all other avenues before making a family matter the business of a court. Once that machine starts rolling, it can be hard to stop.
If you do have to have recourse to a legal restraint, be sure that someone who understands the process and its ramifications is advising you. And be prepared to spend some money.
Maybe someone who has undergone family arbitration could tell you what that’s like and whether it would be better to try that sort of intervention before seeking a RO.