A sacred cow is something which is immune to criticism by virtue of its high status. This term is often used in a sardonic way, to describe something which is excessively venerated to the point that people are afraid to criticize it. When discussing a sacred cow, the implication is that it must be handled very carefully to avoid causing offense. This slang term is used in many English-speaking countries, although some people find it offensive because of its origins.

This English slang term references the status held by cows in Hindu culture, where the cow is regarded as a sacred animal. In India, where the Hindu faith is widespread, cows are allowed to freely wander the streets, and they must be treated with respect in accordance with their status. In the 1800s, numerous European visitors to India wrote back about the sacred cow, and many people came to believe that cows were sacred in all Asian religions, not just Hinduism.

By 1890s, newspapers were comparing people and situations to sacred cows, and around 1910, they went a step further and dropped the comparison, referring to situations specifically as sacred cows. By this time, the term had entered the English lexicon, and it was in widespread use. It is often used in political polemic, usually in a way which suggests that a person or situation could actually stand closer examination and perhaps some critical thought.

For people of the Hindu faith, this slang term could be considered potentially offensive, as it references their religion in a rather uncomplimentary way. The term essentially makes fun of the concept of the sacred cow in Hindu faith, suggesting that the entire idea is ludicrous, and it also propagates the notion that cows are generally viewed as sacred in Asia, which is not the case. While cows certainly do play a role in some Asian religions, it is only in Hinduism that they are considered holy.

You may hear someone describe an established practice as a “sacred cow,” as in “don't bother trying to change this,” and people, situations, and events may also be called sacred cows. The topic of the sacred cow often comes up in political campaigning, usually with the goal of assaulting a political opponent's position or life history, suggesting that a politician is hiding behind a sacred cow, rather than facing criticism head-on.