You can describe a sick person as having a disease or illness. They may be contagious, have symptoms, or be in the hospital. The most common adjectives that you can use; Achy, Arthritic, Bad, Bloated, Bloody, Bored, Bulging, Burning, Cancerous, Cheesy, Chipped, Congested, Contagious, Coughing, Crooked, Dizzy, Exhausted, Fatigued, Faulty, Feverish, Fluid-filled , Frail etc.