We're kicking things off with the nuclear bomb of profanity: The 'F' word.
With examples from I Love You Phillip Morris, The Boondock Saints, Supernatural, Shakespeare, and more.
While many of the profanities in the English language vary in intensity as you travel around the world, 'fuck' remains pretty consistent as one of the top "Words Most Likely To Send You to The Principal's Office."
No one's quite sure how this happened, or if the word has always been considered 'obscene.' The earliest written appearance of the word, in a poem written in English and Latin dating before 1500, uses 'fuck' to mean 'have sex,' and that meaning has never changed. (You can see the original manuscript here.)
The actual origins of the word are unclear; various theories include Germanic languages and Latin, though Latin's a long shot. The word was almost certainly considered obscene by Shakespeare's time, because the Bard never uses the word. Instead, for example, in Henry V, Pistol threatens:
Master Fer! I'll fer him, and firk him, and ferret
him: discuss the same in French unto him.
"Firk" is the first, but not last, euphemism we'll be seeing for 'fuck.'
As five hundred years passed, 'fuck' gained additional flexibility. Our friends at Wikipedia say:
"Fuck" can often be used as a verb, adverb, adjective, imperative, interjection, and noun. It has various metaphorical meanings.
This can result in lines like this one from I Love You Philip Morris:
Fuck you, calm down! Calm you, fucking down!
In his defense, Steven Russell is quite upset at the time. Steven is only using 'fuck' as a verb here, though. Here's Philip Morris using the word as an adjective:
I realize all that crazy shit you did, in your own fucked-up way, was for me.
"Fuck" can indicate an unfortunate situation:
"Bobby called," Sam said. "The good news is he's got the artifact. The bad news is he's in Tampa."
"So we're fucked," Dean said.
It's also used to add emphasis:
"What the fuck do you think you're doing?" Fick asked.
Kevin Smith and Quentin Tarantino are best known for using 'fuck' with great creativity, but let's not forget this fine line from The Boondock Saints:
What did you do?! Fuckin'... what the fuckin' fuck! Who the fuck, fucked this fuckin'? fuck. How did you two fuckin', fucks?.... FUCK!
Outside the purview of R-rated movies and HBO original series, 'fuck' is a more challenging word to use. Some canon sources, especially those set in sci-fi and fantasy worlds, use euphemisms. Here are a few of the more well-known examples:
Battlestar Galactica uses "frak":
I guaran-frakkin-tee you, I will put you down this time for good.
Farscape uses "frell," often as a cross between 'fuck' and 'hell':
Pop the frelling bubble! Make the wormhole collapse!
Scrubs uses "frick," more sparingly:
Frick on a stick!
Many American prime-time shows, however, are profanity-free. (The FCC ensures broadcast TV keeps swearing to a minimum, only allowing 'fleeting' profanity in live broadcasts, and most cable shows follow suit.) Supernatural played with this convention in the episode Ghostfacers, which parodied reality TV. In it, Sam and Dean are shown swearing, with the profanities 'bleeped out' for TV viewing, like a reality TV show. (The characters in Metalocalypse also swear; in broadcast the profanities are disguised with guitar licks.)
A fanwriter has a certain amount of flexibility when introducing -- or not introducing -- profanities such as 'fuck' to canons that don't include the word. Taking setting into account will probably help. For example: Stargate and Generation Kill both feature Marines. Even though Stargate kept profanity out of the show and Generation Kill (whose adaptation was broadcast on HBO) was rife with it, an author might well include a liberal dose of profanity in stories for both fandoms. But 'fuck' wouldn't feel appropriate in the average Miss Marple or Jeeves and Wooster story.
However the fuck you use it, 'fuck' can either add flavor to a story or throw a reader completely out of the narrative, so be careful!