An anthropophagus is a person who eats the flesh of other people. An anthropophagus is a cannibal.
Cannibal has such a scary, chilling sound and man-eater sounds more like a femme fatale these days. If you need to characterize an eater of human flesh in a more technical, less emotion-ridden way, you might use this Greek-derived word. The first half of this word relates to humans (much like anthropology) while the second half appears in many words related to eating. With luck, the only place you’ll ever run into an anthropophagus is in a book.