Sometimes you can tell just from looking at someone's pale face and lips that they're anemic. If you're anemic, your body has a shortage of healthy red blood cells.
Often when someone's diagnosed as being anemic, they're counseled to eat more foods that contain iron, which can help rebuild the red blood cells in their body. Besides looking pale, an anemic person is often tired and weak. Another, non-medical, meaning of anemic is simply "lacking in vitality or energy." Both meanings come originally from the Greek anaimia, "lack of blood." The British spelling of anemic is anaemic.