Simply, when one is outraged beyond all other words, when there is nothing left to do but put on your Frenchiest of accents, point your pointiest finger, and cry, J'accuse!.
It means "I accuse [you]" in the French.
This is half a storied work of public journalism, half Memetic Mutation. It goes like this:
Once upon a time in France, a renowned writer named Émile Zola penned a scathing open letter to the President (published in liberal publisher Georges Clemenceau's newspaper L'Aurore on January 13, 1898) that accused the government of France's Third Republic of anti-Semitism and corruption in its handling of the Dreyfus Affair of 1894 — in which an innocent French Army officer, Alfred Dreyfus, who just happened to be Jewish, was used as a scapegoat in a German espionage case (France had recently lost a war to Germany and despised them), when it was quite clear to everyone that the only thing that Dreyfus was guilty of was being Jewish and from the region of Alsace (that was currently under German control). The letter pointed out the weakness of the evidence and several clear occurrences of judicial error and prejudice during Dreyfus's trial, and formally named and accused scores of people of everything from incompetence to crimes against justice and humanity; for someone so prominent and respected as Zola to write something so harsh was a big deal, and for that Clemenceau (who loved picking political fights) set the sensationalist headline, in giant, bold letters: "J'Accuse...!".
Naturally, the conservative French establishment was scandalized, and in retaliation Zola was rapidly charged with and convicted for libel (which he had predicted he would be in the article, even citing the specific laws he would be charged with breaking) and had to flee to England for a year, until the bureaucrats then in power were removed. Dreyfus had been sentenced to life in prison on Devil's Island; he appealed his case multiple times, but it was not until 1906, twelve years after his trial, that his conviction was actually annulled.
- Doonesbury once had a drug sniffing dog point at Zonker and say "J'accuse!".
- The Far Side had a panel where a live lobster bursts into a kitchen, points his claw at a chef cooking lobster, and shouts, "J'accuse!"
- And Pogo got in on it.
Churchy LaFemme: J'accuse!
Howland: Don't you call me no j'accuse!
- In A.A. Pessimal's Hogswatchtime story Il se Passait au Nuit de Pere Porcher, DEATH is detained by the Klatchian Foreign Legion, who, whatever else they may forget, always remember a deserter. note . DEATH is arrested with the formula of "J'accuse!" and is court-martialled. But Discworld literal-mindedness takes over and the court goes off at a tangent concerning a soldier called Corporal Jack Hughes, Hughes the Booze from Third Batallion...
- J'Accuse: A French zombie movie released in the 1920s filled with as much political weight as can be. The Zombie Apocalypse is the sudden uprising of the French dead of WWI, coming back to condemn the guilty living who sent them to die. The whole film is an anti-war polemic, which the director convinced the army was going to be a propaganda flick, so they gave him real soldiers for actors — 80% of whom died once they went back to the front.
- The Life of Émile Zola: Award-winning 1937 film about the Trope Namer and Zola's crusade on behalf of Alfred Dreyfus (the Translation Convention is in full effect here, so Zola's letter is printed as "I Accuse!").
- There's also a 1958 film about Dreyfus, fittingly entitled I Accuse!, directed by and starring Jose Ferrer, along with Anton Walbrook and Viveca Lindfors.
- Discworld: In Going Postal the hero Moist von Lipwig uses a technically complicated plot to replace a message used in a bet with his enemy Reacher Gilt to do a wonderful reveal of Reacher's entire plot and bring him and his minions down using this trope.
- The first Odd Thomas book contains a gag about how, while Odd is towing a dead body out of an apartment, he's trying to be quiet, except that he has to dump it over the railing. As he comes down the stairs, he guesses that no one heard him because no one runs at him yelling J'accuse!
- The historical novel An Officer and a Spy, about the Dreyfus Affair, includes a scene where the protagonist (Georges Picquart) learns about the publishing of Zola's famous letter. The text includes long extracts of the letter.
- On 30 Rock, Liz Lemon utters this phrase when some of Frank's cigarettes go missing, implying that he hasn't quit smoking. Turns out she ate them in her sleep.
- 'Allo 'Allo!: In an unusual subversion of the show's trope of using Just a Stupid Accent as a Translation Convention for whatever language is actually being spoken. Lt. Gruber relates a dream he had of Rene saying "J'accuse! J'accuse!" and responds "Who is this "Jack Hughes"?" (Gruber believes he killed Rene with a firing squad and the Rene currently in the show is Rene posing as his own twin brother also called Rene). At the end of the episode Rene gets stuck on a giant aerial rising out of a grave (they'd hidden a transmitter in Rene's crypt since it was empty) and Gruber sees this figure of Rene rising out of the grave (looking sheepish) and faints. Helga then says "Well at least he didn't mention this "Jack Hughes". Roll credits.
- Lester lets one fly in a final season episode of Chuck after discovering he and Jeff have been Locked Out of the Loop regarding Chuck's double life.
- Doctor Who: In "The End of the World", Lady Cassandra does this when the Ninth Doctor seemingly discovers the culprit that was attempting to kill them all because she's hoping he won't realize that she's the real culprit. He does.
- Robert says this to Raymond in an episode of Everybody Loves Raymond. Marie, who's taking French classes, says "Ooh! Ray! He's accusing you!"
- In Glee Stoner Brett yells this during a Brittany Spears performance by the New Directions.
- Modern Family had Cam say this after he discovered his husband was keeping his larger clothes in case his diet fails, specifically because it was more dramatic than other ways.
- In The West Wing episode "The Indians in the Lobby", President Bartlet attempted to use this on his wife Abbey when he finds out it's her fault they were going to celebrate Thanksgiving in Camp David rather than their family farm in New Hampshire. It didn't work out so well, though:
- Sonic Youth released "J'accuse, Ted Hughes". It's not Just for Pun, that's a controversial English poet who developed a Hatedom after Sylvia Plath (whom Hughes had just recently divorced) killed herself.
- The Arthur music album Arthur's Really Rockin' Music Mix has the song "Fern's Detective Tango," which is based on the events of the episode "Binky Rules." In the song, Fern sings about the various reasons why certain characters couldn't have been responsible for the graffiti reading "BINKY RULES," before finally declaring, "Binky, j'accuse!"
- In Eternal Sonata, this is the name of one of the attacks of Fugue, one of the Big Bad Count Waltz's minions. Since Calling Your Attacks is fully in effect, you get to hear it its full glory.
Fugue: You peasants can never appreciate beauty of this kind. J'accuse!
- The Simpsons: Hit & Run
- Guybrush lets out the line at one point in the fourth chapter of Tales of Monkey Island.
- Futurama: Zoidberg says this once, the joke being that he's not French but Ambiguously Jewish.
- King of the Hill: Gilbert says it to Bill while ranting about his plan to sell the family's barbecue sauce.
- Shadow Raiders: An episode title. The episode deals with the trial of a military officer that threatens society itself, no less.
- On one episode of The Simpsons, Lisa complained about her French teacher not actually speaking French. "J'accuse!" "...What the hell is this broad talkin' about?"
- Used in South Park in the April Fool's Day episode "Terrence and Philip in: Not Without My Anus", only to be sent up with a Chewbacca Defense.