I'm going to call my sister retarded for not accepting our criminal relative's planned inheritance
Why would you think she is mentally disabled because of that?
She just is.
You shouldn't call your sister names. She's an adult and has all the rights to make decisions for herself so you should leave it up to her whether to accept the inheritance or not.
You are being close minded. I'm going to tell her how wrong she is for not following the plan.
It is perfectly fine to tell someone what you think about a situation, however you calling them this derogatory name is not the way to do it. Effective and open communication is the best way to solve your issues with one another.