To write this in reported speech, you'll need to rephrase the original thought into a grammatically correct sentence. Here are a few ways to do that:
Option 1: Focus on the desire to be rude
* "I wished I could be rude."
* "I wished I could say something rude."
Option 2: Focus on the situation prompting the rude thought
* "I wished I could tell him off." (Replace "him" with the actual person you're referring to)
* "I wished I could have given her a piece of my mind." (Replace "her" with the actual person you're referring to)
Option 3: Focus on the person's behavior prompting the rude thought
* "I wished I could tell him how rude he was being."
* "I wished I could tell her that her behavior was unacceptable."
Remember to choose the option that best reflects the specific situation and your intended meaning.