Can I be fired for calling someone a name in Tennessee

This depends upon your employer's rules. In Georgia, for instance, the employment relationship is "at will." (Tennessee's is probably the same.) That means an employer can fire a person for any reason or no reason - and the employee can quit for any reason, or no reason. The employer has the right to establish the rules of behavior for its workplace. As long as the employer does not enforce such rules or standards in an illegally-discriminatory way (i.e., this means to base the enforcement decision on your race, color, creed, religion, gender, age (if you're over 40, disability (if you're qualified for your job), status as a member of the armed forces oe veteran, or as retaliation for the exercise of federally protected rights, the employer is free to terminate you for any reason -unless you have a contract that limits the employer's right to do so.