Taboo n. : A total prohibition of intercourse with, use of, or approach to, a given person or thing under pain of death, -- an interdict of religious origin and authority, formerly common in the islands of Polynesia; interdiction.

Taboo v. t. : To put under taboo; to forbid, or to forbid the use of; to interdict approach to, or use of; as, to taboo the ground set apart as a sanctuary for criminals.

Example:
What are Taboo topics to discuss with pregnant women in America?

Taxonomy
taboo, society, prohibition, tabu, incest taboos, free encyclopedia, dietary restrictions, taboo topics, Captain James Cook, English, modern society, tapu, behaviors, 2007-06-05, search, Polynesian cultures, Kingdom of Tonga, history.

Defination from the web:
taboo is a strong social prohibition (or ban) relating to any area of human activity or social custom that is sacred and forbidden. ... The use of taboo in English dates back to 1777 when English explorer, Captain James Cook, visited Tonga, a place he named "the Friendly Islands" ...