Before you terminate, obtain legal advice regarding the amount of severance that is appropriate in the circumstances. In most cases, employees are entitled to a severance package, even if underperforming in the job. Offering a reasonable severance package in line with the employee’s legal entitlements reduces the risk that the employee feels disgruntled about the manner of dismissal.
Should the employee end up publicly badmouthing the company, you have some options. Start by persuading the employee to voluntarily remove the post. A cease-and-desist letter and threat of legal action is an effective strategy to encourage compliance. If that fails, the company may pursue a defamation claim through the courts. The company can be awarded monetary damages and/or a court order requiring the employee to delete the post.
Maybe be a good boss in the first place, so nobody has any reason to badmouth you.
I'm worried about my ex-employer tormenting future employees. What can I do?