A gaunt face refers to a face that appears thin and bony. The term is usually used to describe the face of someone who looks sick, malnourished, or unhealthy. It generally isn’t used to describe a naturally thin but healthy-looking face.
As you age, your face tends to lose fat. This loss of fat can cause sunken cheeks and a more angular appearance. Certain lifestyle habits, such as not wearing sunscreen, not eating a balanced diet, and smoking, can age your face more quickly. Subcutaneous fat, or the fat beneath your skin, gives your face volume and plumpness. As you get older, you tend to lose some of this fat. This loss makes your face appear thinner and bonier. As you age, your skin loses elasticity due to a reduction in the proteins, collagen and elastin. Losing these proteins can cause more sagging skin and wrinkles.