Casey Anthony -- The Government's Got My Back!!

Days after Casey Anthony cleared her own name ... someone else was already trying to hijack it -- by filing an application to trademark the words "Casey Anthony" ... WITHOUT her permission.

TMZ has learned ... a San Francisco-based company called Grant Media filed a U.S. Trademark application on July 10 ... hoping to lock down the rights to use the name "Casey Anthony" for entertainment purposes.

But the Trademark office put a big, fat REJECTION on the application -- claiming the company could not prove they have ANY connection with Casey Anthony at all.

According to docs obtained by TMZ, the Trademark office explains, "[Anthony] is not connected with the services sold by the applicant under the mark. Moreover, due to her fame, purchasers would presume a connection between Casey Anthony and the entertainment services."

Sources close to Casey confirm ... Anthony has NO connection to Grant Media ... and her lawyers are ready to take action against ANYONE who attempts to profit off of her name.