Language evolution used to be slow.

Maybe not geologic-eon slow, but it took a while.

Take the simple word ooh. It started out as a noun (“They let out an ooh when she entered the room”) and interjection (“Ooh, an interjection!”) 416 years ago, in 1602. It would be an additional 328 years before ooh became a verb (“They oohed when she entered the room”), in 1930.

But like geologic eons buckling under a changing climate, linguistic evolution has accelerated. Words enter the lexicon, nouns become verbs, and definitions change in a comparative blink of an eye.

Here, a roundup of words that mean something different for 2019 than they did a year ago.

Collusion. Old definition: “secret agreement or cooperation especially for an illegal or deceitful purpose,” dating back to the 14th century.

New definition: Living in the White House, you wield outsize influence over language. When Trump tweets the word collusion 156 times — which he has, as of this writing — it makes an impact.

Sometime this year, his usage started to change.

Feb. 17: “[T]he only Collusion was between Russia and Crooked H, the DNC and the Dems.”

April 18: “[T]here was NO COLLUSION (except by the Dems)!”

June 2: “We now know there was Russian collusion, with Russians and the Democrats.”

There are many more examples.

Then he twisted the definition further. July 31: “Collusion is not a crime, but that doesn’t matter because there was No Collusion (except by Crooked Hillary and the Democrats)!”

Aug. 16: “[T]he [Boston] Globe is in COLLUSION with other papers on free press.”

Dec. 16: “A REAL scandal is the one sided coverage, hour by hour, of networks like NBC & Democrat spin machines like Saturday Night Live. It is all nothing less than unfair news coverage and Dem commercials. Should be tested in courts, can’t be legal? Only defame & belittle! Collusion?”

To recap: Over 2018, collusion evolved from something Donald Trump claims he didn’t do to something that Russia, the DNC, and Hillary Clinton did do; to something that isn’t actually a crime; to newspapers reporting the news; to SNL.

If the effect is dizzying, the goal is obvious: to deprive collusion of all meaning. That way, when special prosecutor Robert Mueller’s report arrives, it won’t matter whether it implicates Trump in collusion because everyone will have forgotten what the word means anyway.

BDE. Old definition: an acronym for the Hebrew Baruch dayan ha’emet, meaning “blessed is the true judge.” Frequently said to those in mourning.

New definition: a very different acronym, which starts with big and ends in energy. (The middle word is an anatomical vulgarity unprintable in a family newspaper, but you don’t have to have one to display BDE.) First used regarding Anthony Bourdain’s confidence and swagger. Popularized by Ariana Grande regarding Pete Davidson’s, um, davidson. Has celebrated celebs including Idris Elba, Rihanna, David Brooks, Mr. Met, Ginny Weasley, and the 2018 South Korea men’s World Cup team.

Nothing to mourn here.

Squee. Old definition: an interjection indicating excitement (“It’s a puppy! Squee!”).

New definition: a noun, often accompanied by P.J. and Moose. 2018 highlights include Matt Damon’s emotional usage in one of SNL’s funniest sketches all season. Lowlights include Brett Kavanaugh’s emotional usage in one of the U.S. Senate’s least funny confirmation hearings all season.

Democrat. Old definition: a noun meaning “member of the Democratic Party.”

New definition: an adjective, used pejoratively, for ideas that may or may not have anything to do with Democrats. Witness the phonetic harshness of “Democrat policies” or “Democrat politicians” over Democratic.

This one isn’t entirely new: Politicians have revived this slur periodically, as noted by William Safire in a 1996 National Journal article: “For years, Republicans have irked their opponents with pointed use of ‘Democrat’ — as in Democrat Party or Democrat wars.” George W. Bush was fond of both malapropisms and using Democrat as an adjective; The New Yorker wrote in 2006, “ ‘Democrat Party’ is jarring verging on ugly. It fairly screams ‘rat.’ ”

But if this particular misuse was relegated to the wilderness for a while, Trump has brought it roaring back. At a rally on July 5, he said: “By the way, I call it the Democrat Party. It sounds better rhetorically. … I guess I speak well. … They never say I’m a great speaker.”

Gritty. Old definition: an adjective meaning courageously persistent. Uncompromisingly real. Philadelphia.

New definition: a noun meaning terrifying orange ice monster. Deranged embodiment of our city’s hopes and fears. Subject of the best resolution our City Council ever adopted. Philadelphia.

The Angry Grammarian looks at how language, grammar, and punctuation shape our world, and will appear biweekly. That’s every other week, not twice a week, friends. Send comments, questions, and conjunctive adverbs to