This word is used to
refer to the eating of dead
human beings by other human beings, or occasionally to another species where some individuals eat members of the same species.
Historically, the practice is rather rare. Any parasites or diseases which afflicted your dinner may be a danger to you, especially if it is not thoroughly cooked. The victim is dead - how healthy could they be? Of course, if you killed after a tough battle the chance that they had a horrible disease is reduced.
Sometimes cannabalism is found in regions where the population is extremely short of animal protein. A brave Aztec warrior who brought a prisoner to be sacrificed by the priests might well be rewarded with a leg.
Otherwise cannabalism can be a ritual practiced under rare circumstances. One might eat certain parts of a formidable enemy hoping to benefit from some of his attributes. Even where it is regarded as a horror, it might be used to create a rare secret bond between a small group.