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f(x) is a South Korea-based girl group formed by S.M. Entertainment in 2009. In August 2015, it was announced that Sulli had officially left the group to focus on acting. The remaining members: Victoria, Amber, Luna, and Krystal, continued as a group, releasing their fourth studio album, 4 Walls, in October.
Why did Fifth Harmony Camila's departure reminded me of Sulli leaving F(X)...?
f(x) by jennie kim December 28, 2016
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f(x) (Korean: 에프엑스; pronounced /ˌɛf ˈɛks/) is a South Korean girl band formed by SM Entertainment. The group made their debut on September 1, 2009.

The members are:
- Victoria (Leader, Lead Dancer)
- Amber (Main Rapper)
- Luna (Lead Vocal, Main Dancer)
- Sulli (Vocal, Rapper)
- Krystal (Maknae, Main Singer, Main Dancer)
A : Ugh, I don't get this whole f(x) thingy.. (Looking at the math book)
B : What? how come you don't get them?! F(x) is like one of the hottest girl groups from South Korea!
A : Eh?
f(x) by affxtionate June 20, 2011
Raleigh slang for a function, as in a party. More commonly used as abbreviation while typing.

Pronounced “f of x”.
Yo how was the f(x) last night?

Dammmn twelve pulln up to the f(x).
f(x) by Destroyer of Toilets August 8, 2026
The first derivative of a function. See calculus.
If f(x) is equal to x^2+2x+5
then f'(x) is equal to 2x+2.
f'(x) by ManMan36 May 23, 2016
when the output of a particular function is always equal to 11. Common notation variations include fx11, fx=ll, or fxll.
"Damn, I love functions, especially that f(x)=11 thing, its so easy" - some random guy.
"*moans* fxll-chan" - Owen
f(x)=11 by s3m3nd3m0n June 10, 2022
A zombie face emoticon. The f's represent hands.
Person 1: Dude are you awake?

Person 2: f(x_x)f

Person 1: What the fuck?

Person 2: I'm a zombie
f(x_x)f by Malignant Mind October 23, 2008

f(x) = e^x 

The only function in the world that satisfies ∫f(x)dx = f(x) and d/dx f(x) = f(x). Very dumb.
Question: ∫f(x) = f(x)
Because ∫f(x) = e^x
Therefore, the solution is e^x
f(x) = e^x by BladeX123uWu December 18, 2022
More from Urban Dictionary

Surf Dracula Syndrome 

A phenomenon in film/television series, most notably streaming series, where the main premise is drawn out to such a point that it takes an entire season or more to get the parts of the series the audience is actually interested in seeing.

For example, if a series is titled "Surf Dracula," a majority of viewers would tune in expecting to see Dracula surfing by the first or second episode. However, the entire first season would instead be tedious padding and backstory before finally ending with Dracula surfing in the last five minutes of the season finale.
I watched "Smallville" on Netflix the other day. Dude, it was ten seasons of filler before he finally flew! Major Surf Dracula Syndrome!
Word of the Day on October 24, 2026

Northstarring

Finding your way back to the truth by fixing on one verified fact and working out from there, the way you navigate by the North Star when everything around you is spinning.
Rumours were flying everywhere, so she went northstarring — one checked fact at a time.
Northstarring by Light Bearer October 22, 2026
Word of the Day on October 23, 2026

Plate of Brown 

A plate of brown consists of foods that have little to no nutritional value, and are typically deep fried. A true plate of brown will also be accompanied by a dark soda.
Wanna go to meal hall & grab a plate of brown?
Plate of Brown by Cheddar Craigson September 18, 2020
Word of the Day on October 22, 2026

Larpenomics

When finance content creators rent out fancy cars and flex cash to seem richer than they really are in order to promote and sell their “get rich quick” courses.
Andrew Tate has mastered the field of larpenomics
Larpenomics by Rbois09 October 21, 2026
Word of the Day on October 21, 2026
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