The term for a sick person unable to work is "sick leave" or more generally referred to as being "disabled" or "ill". When an employee is unable to perform their job due to illness, they may request sick leave, which allows them to take time off without losing pay or employment. This term encompasses a range of health issues, from acute illnesses like the flu to chronic conditions that hinder one's ability to work regularly. Employers often have policies in place to support their employees during their time of illness, which may include benefits such as paid sick leave, disability accommodations, and healthcare resources.