Please provide me with an explanation as to what the term "gross incompetence" means and also how it can be proven by an employer, and then defended by the employee?
Incompetence would be failure to meet a standard of performance set by your employer. Gross incompetence would therefore mean a more serious breach. An employer would prove this by providing evidence that your work was not up to scratch. Similarily, an employee would have to provide evidence to the contrary.
Gross incompetence is when someone does something badly and their boss needs them so they have to keep them and in dog with a blog Ellen does stuff badly and she asks to get fired