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AF stands for “as fuck” on the internet and is used to emphasize something in an either humorous or serious way. The lowercase form, af, communicates a lighter and more relaxed tone.

You’ve probably seen “AF” on your social media feed at least once. Here’s what this useful internet modifier means and how to use it to spice up your messages.

As F***

AF means “as fuck.” On the internet, it’s an intensifier that emphasizes the meaning of a preceding adjective or adverb. For example, if you want to tell your friend that you’re very angry, you’d say, “I’m mad AF.” You can find this acronym on all corners of the web, from social media posts on websites like Twitter and Reddit to direct messages between friends.

Internet users write the acronym in both the uppercase “AF” and the lowercase “af.” You should note that these two tend to vary in intensity, with “AF” appearing more intense while “af” is more tempered. However, these variations still depend on the context, so read other people’s messages carefully before coming to conclusions. AF can also be written as “ASF,” but this variety is uncommon.

It’s synonymous with other intensifiers, such as “very” or “incredibly.” There are also similar slang phrases, like “as hell” and “as anything.” Unlike other slang terms, you typically don’t combine AF with other internet acronyms. Most acronyms already convey intense feelings, such as NFW or “no f***ing way” and ROFL or “rolling on the floor laughing.”

There are several other definitions for this acronym you should be aware of. In medicine, AF can refer to “atrial fibrillation,” an irregular heartbeat more commonly known as “AFib” or “arrhythmia.” AF may also refer to the “air force” in some countries.

The History of AF

Compared to other web acronyms that we’ve covered, AF is a more recent invention. The earliest definition for AF on the internet slang repository Urban Dictionary dates back to 2011 and reads, “the acronym stands for as fuck.”

Unlike shortened slang terms that originated in the internet chatroom days, AF came from the social media boom of the early 2010s. The phrase “as f***” was not widespread yet, and its shortened version would come to the internet even later. Nowadays, it’s one of the most common slang acronyms on the internet.

You’ll find this acronym on popular Tweets, song lyrics, and movies. Many young people also say it aloud, either by spelling out the letters “AF” or saying it as one syllable, “af.” In the summer, you might hear someone say, “it’s hot af out today.”

Intense AF

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You can use AF to make nearly any adjective or adverb more intense. A common feature of AF is that it displays strong feelings from the person typing it.

People can use the acronym to display extremely negative emotions towards something. For example, if someone is deeply frustrated with their job, they might say “I’m tired AF” to describe their exhaustion. They might also say, “my boss is annoying AF” if they have unpleasant feelings towards their supervisor.

On the other hand, AF can convey positive feelings towards something. For example, if you’re excited about a trip you’re going on with your partner, you might tell them that “I’m excited af.” When you’re in an especially festive mood, you might text your friend, “I’m happy af!”

You can also use AF to describe inanimate objects, situations, or verb modifiers. For example, if someone is running significantly faster than expected, you’d say, “they’re running fast af!” Likewise, if you’re browsing an online store and are shocked by the prices, you might tweet, “this is expensive AF!”

One of the most common words used with AF is “crazy.” You’ll see “crazy af” used to describe various situations and things, some of which might not seem that crazy at all. This phrase is occasionally used sarcastically, such as in “wow, this geometry homework is crazy af,” so try to read between the lines if you see this phrase.

How to Use AF

Using AF in your internet posts is relatively straightforward. Simply add it to the end of an adjective or adverb that you want to intensify. You can use both lowercase and uppercase, but the lowercase version has become more common in recent years. Note that this term is very informal, so avoid using it in business correspondence.

Here are a few examples of AF in action:

  • “That entrance test was hard AF.”
  • “I’m worried af about my interview tomorrow!’
  • “I can’t believe it! That’s crazy AF!”
  • “I saw this creepy horror movie yesterday. The monsters were gross af!”

If you want to learn about other internet slang terms, check out our explainers on TTYL, NVM, and OTOH. You’ll be a web-speak pro soon enough!

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Profile Photo for Vann Vicente Vann Vicente
Vann Vicente has been a technology writer for four years, with a focus on explainers geared towards average consumers. He also works as a digital marketer for a regional e-commerce website. He's invested in internet culture, social media, and how people interact with the web.
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