Idiom meaning, usage examples, facts

1. Don’t suggest that the boss should get rid of one of his secretaries so that we might hire another clerk. The subject of his secretaries is a sacred cow.
2. Even though the country needed to raise more money to pay for military and social programs, the president refused to raise taxes. To him “no new taxes” was a sacred cow that he was unwilling to sacrifice.

The expression originates from the Hindu belief that cows are sacred and cannot be killed or eaten. The expression is frequently used to describe an idea or thing that ought to be changed or altered but cannot be because the authority forbids it.