A taboo is a social prohibition against a particular act, object, or person. It is not just a rule. Breaking a taboo is thought to bring danger, pollution, or supernatural punishment. The word comes from Tongan, where tapu means sacred or forbidden. Taboos exist in every society. Some protect the sacred. Others protect the dead, the vulnerable, or the social order. In many cultures, it is taboo to speak the name of a deceased person, to eat certain animals, or to touch a chief.

Taboos are often enforced by the community rather than by formal law. Fear of pollution, shame, and exclusion do the work. Some taboos have practical functions. A prohibition on eating pork in hot climates may have reduced disease risk. A ban on incest reduces genetic disorders. But not every taboo has a practical explanation. Some mark boundaries between the sacred and the everyday, and that is reason enough.

Common types

• Food taboos: animals or plants that cannot be eaten.
• Ritual taboos: restrictions during ceremonies or initiation.
• Kinship taboos: prohibitions on marriage or sexual contact.
• Sacred taboos: objects or places that cannot be touched.

Taboos are not irrational. They are a way of organizing social life and marking what matters.