WORDS ARE power. Whether used to twist or reveal, language matters, especially that used by the people who govern a nation devoted to free speech. This is why it was such a shock to hear the Department of Health and Human Services instruct some of its divisions, including the Centers for Disease Control and Prevention, to avoid using certain words or phrases in official documents being drafted for next year's budget. It sounds like thought police at work.

If that judgment seems harsh, consider what happens in China, where thought police really exist. China routinely censors articles containing politically sensitive words such as "Taiwan," "Tibet" and "cultural revolution " from publications because it does not want its people to think about them. Writing about democracy could lead to trouble in Belarus, Cuba or Vietnam, too. In Russia, words that refer to gays positively can trigger a penalty. In Saudi Arabia, a blogger, Raif Badawi, sits in jail for his online appeal for a more liberal and secular society.

It is not a far stretch from these examples of misguided censorship abroad to the actions of the HHS language militia. According to Post reporters Lena H. Sun and Juliet Eilperin, policy types at the CDC in Atlanta were told of the list of forbidden terms at a meeting Dec. 14 during a 90-minute briefing to discuss the upcoming budget request. The terms prohibited to use are: "vulnerable," "entitlement," "diversity," "transgender," "fetus," "evidence-based" and "science-based." They also reported that in some cases, the policy folks were given alternatives; instead of "science-based" or "evidence-based," the suggested phrase is "CDC bases its recommendations on science in consideration with community standards and wishes." But in other cases, no replacement words were immediately offered.

The CDC's new director, Brenda Fitzgerald, replied that "there are no banned words at CDC." That's a relief, given the agency's mission, which includes acting as sentinel for public health, warning of threats and responding rapidly to meet them. But Ms. Fitzgerald's assurance does not ease concerns that higher-ups at HHS are insisting on banned words to enforce a political and ideological agenda. Why would they eliminate "vulnerable," "entitlement," "diversity" and "transgender" in a budget document other than to airbrush the ideas out of the underlying policy?

Just as distressing is the attempt to limit the use of "evidence-based" and "science-based." Unfettered scientific research is vital for maintaining public health, even when the results are unpopular with some communities and points of view. Being able to talk about science is absolutely critical in, say, understanding the value of childhood vaccination in preventing the spread of measles. "Fetus" is a scientific word essential to exploring the impact of the Zika virus on the health of infants and pregnant women. And can there be an honest discussion of the health effects of climate change without science and evidence? Does anyone gain by hiding the truth these words express? No. Someone should tell the foolish thought police at HHS to stand down.