Hey there Boots,
What an outrage! How dare your Meowmie call you such a name. What is it with these hoomins anyway? Soncat calls me Boobypants and I have no idea why . So I do understand how you must feel.
First of all, there's no such thing as a kitty brat. I checked my law books and using such a name does qualify as aboose. If you are interested in getting an injunction to put an end to this, please let me know and I'll prepare the papers to be signed by the judge in Cat Court.

Your friend,
Groucho the lawyer
Practice limited to Kitty Krimes and Aboose