It’s commonly said that a fact is what’s expressible by a statement that is “proven” to be true—e.g. statements such as “2+2=4” and “the Pacific is the earth’s largest ocean”—whereas opinions lack proof even when they happen to be true.

Yet in an era when more and more reality is weaponized for political purposes, the difference between fact and opinion is no longer that simple.

Take the concept of alternative facts. Counselor to the President Kellyanne Conway was widely ridiculed last winter for using that phrase in defense of the White House’s apparently inflated estimate of attendance at President Trump’s inauguration. Many assumed that she had just concocted it as a euphemism for ‘lie’. But she hadn’t, exactly.

Like other attorneys, whose profession is amply represented in Washington, Conway would have been familiar with “alternative facts” as a term of art. Examples are given , and the core meaning can be summed up thus: “‘[A]lternative facts’ is a competing version of what the events actually were, based upon evidence available.” Every trial attorney knows that such versions of events arise and clash regularly—sometimes in witness accounts, which are often incompatible with each other, and sometimes in the competing case-summations of prosecutors and defense counsels.

Of course, Conway’s use of the phrase, while it may have been technically accurate, was a weak defense of an assertion that was demonstrably false. But even the accurate use of that phrase to defend a falsehood tends to undermine clear thinking about what is and is not fact.

Playing fast-and-loose with the very concept of fact is by no means limited to the White House or Congress.

Consider the relatively new concept of hate facts, which seems to have originated on the political left. Urban Dictionary defines it thus: “A hate fact is a matter of truth, fact, or reality that supports an argument based on stereotype or prejudice.”

I find that there are many such facts, if you want to call them that. UD’s example is: “Russell relied on hate facts like ‘women have 55% less upper body strength than men’ to defend his opinion that women should be kept out of military combat.” Calling such facts “hate facts” suggests that they are cited for the express purpose of reinforcing invidious prejudices and keeping people down.

But that isn’t necessarily the case. For instance, take the research cited in this CNBC story on why millennials are facing financial hardships. It corroborates common sense and a mass of other research to the effect that family structure matters economically. It supports the idea of a “success sequence”: Graduate (from high school, trade school, or college), get a steady job, marry the one you love, then have kids. Few people who follow that order and stick to it remain in poverty, even if they started there.

But whenever I point out these financial realities, somebody always protests that I’m blaming the poor for their plight and attacking single moms. I’m citing a hate fact, even if I’m not interested in blaming entire classes of people.

The word “fact” serves its purpose much better when not preceded by lawyerly or political adjectives. Let’s keep it that way.