Confusingly, many idioms don’t look much different than what most of us call slang. Why not call a spade a spade? Is there a difference between an idiom and slang? In fact, there is not. The only difference between slang and any other commonly used parts of the language is that slang is not yet (and may never be) commonly used by all speakers of the language.
Quick Summary: Slang vs. Idioms
- The Main Difference: Reach and time. Slang is informal language used by specific groups (like “aura points” in 2026). An idiom is a fixed phrase used and understood by the general population (like “raining cats and dogs”).
- The Waiting Room: Most idioms start as slang. If a slang term survives long enough and becomes a “dead metaphor” (where we forget its literal origin), it graduates to an idiom.
- Why it Matters: Slang adds modern flavor and “cool factor,” while idioms provide a timeless structure for clear communication across generations.
- The “Colloquial” Middle Ground: Regional, everyday informal speech—like calling a soft drink “pop”—bridges the gap between the two.
Definition of Idiom
Linguists do not agree on one universally accepted definition of an idiom. However, a fairly standard definition is “two or more words used together as a unit that has a special meaning not derived from the meanings of the words separately.”
Slang Definition
Here is how the Oxford English Dictionary defines slang: “A type of language consisting of words and phrases that are regarded as very informal, are more common in speech than writing, and are typically restricted to a particular context or group of people.”
Once people accept a slang term or phrase and everyone begins to use it widely, throughout the culture, rather than by certain groups, it is no longer slang.
Many idioms are used in formal books, and many informal idioms are used in everyday conversation. However, some idioms are slang phrases. These may be considered rude, annoying, uncouth, etc., but they are still idioms.
Slang is often restricted to a particular context or group of people. A classic example of this is the financial world; there are dozens of American slang terms for money that people use every day, from ‘bucks’ to ‘dough,’ illustrating how informal language fills specific needs in our social interactions.”
Idioms and Slang Overlap and Co-Mingle
Why should it be an idiom if I say, it’s raining cats and dogs but slang if I say that’s such a cop-out? As common as the idiom “cop-out” is, you won’t hear people of all ages and walks of life saying it, but anyone might say “it’s raining cats and dogs” to refer to a heavy downpour. Both are idioms, regardless.
For that matter, a “catchphrase” may well be an idiom. We say “read my lips” to mean listen to what I’m saying very closely. But, it’s also a catchphrase, often used mockingly and associated with President George H.W. Bush, who said it during his campaign, “Read my lips; no new taxes.” Some idioms are also considered aphorisms.
An aphorism is a short saying that conveys a general truth, sometimes called a proverb. Example: “The only thing we have to fear, is fear itself.”
Idioms are used like words. Therefore, some are heard so much they become cliches. For example, I used a cliche above, call a spade a spade. This phrase is often considered hackneyed, perhaps because it has been used in so many dime detective novels. It fits the definition of an idiom quite well, though.
In other words, all these categories can overlap. While not all slang phrases are idioms, not all idioms are different than slang.
Current Slang Phrases (2025 to 2026) That Have Not Quite Reached Idiom Status
1. “Aura Points”
- Meaning: An imaginary currency used to measure how “cool” or “uncool” someone is based on their actions.
- Example: “Tripping in front of your crush is -1,000 aura points.”
- Why it’s not an idiom yet: It is still heavily tied to social media “vibe” culture and hasn’t yet become a standard way for the general public to describe reputation.
2. “6-7” (Six-Seven)
- Meaning: Something that is “so-so,” mediocre, or just okay.
- Example: “The new movie was 6-7—not great, but not terrible.”
- Why it’s not an idiom yet: This emerged as Dictionary.com’s 2025 Word of the Year specifically as a Gen Alpha catchall term. It’s still highly niche and often misunderstood by older speakers.
3. “Aura Farming”
- Meaning: Intentionally doing things—often performative or aesthetic—to increase one’s perceived coolness or “aura.”
- Example: “He’s just posting gym selfies to start aura farming.”
- Why it’s not an idiom yet: It’s a very specific digital behavior that hasn’t translated into a broad metaphor for character-building in the real world.
4. “404 Coded”
- Meaning: Used to describe someone who is “not all there,” confused, or acting clueless (referencing the “404 Not Found” web error).
- Example: “I asked him for the report, but he just looked at me; he’s totally 404 coded.”
- Why it’s not an idiom yet: While “404” is a known tech term, using it as a personality descriptor is still relatively new and restricted to younger, tech-savvy circles.
5. “Crashout” / “D1 Crashout”
- Meaning: To have a sudden, extreme emotional outburst or to lose one’s temper over something small. “D1” implies it’s at a “Division 1” (elite) level of intensity.
- Example: “He’s about to crashout because they ran out of spicy nuggets.”
- Why it’s not an idiom yet: While it’s gaining traction, it’s still seen as “street” or “internet” slang and lacks the formal acceptance of an idiom like “flying off the handle.”
6. “Brain Rot”
- Meaning: Low-quality, nonsensical, or “slop” content found online that feels like it’s making you less intelligent.
- Example: “I’ve been scrolling for three hours; this is pure brain rot.”
- Why it’s not an idiom yet: Though very common in 2025, it is still used primarily to describe internet consumption rather than as a general term for stupidity or boredom.
| Slang Term | 2025/2026 Meaning | Likely to become an Idiom? |
| Aura Points | Social credit/coolness level | Maybe – “Vibe” stuck around; this might too. |
| 6-7 | Mediocre/So-so | Unlikely – Very trend-specific and may fade. |
| Cooked | In trouble or “done for” | High – Already seeing cross-generational use. |
| Unc | Calling someone “old” | Medium – Replaces “Boomer” but might be replaced itself. |
| Slang Term | 2025/2026 Meaning | Likely to become an Idiom? |
| Aura Points | Social credit/coolness level | Maybe – “Vibe” stuck around; this might too. |
| 6-7 | Mediocre/So-so | Unlikely – Very trend-specific and may fade. |
| Cooked | In trouble or “done for” | High – Already seeing cross-generational use. |
| Unc | Calling someone “old” | Medium – Replaces “Boomer” but might be replaced itself. |
The Path from Slang to Idiom
One thing you’ll notice about idioms, if you think about them as you use them, is that you do not think about their original meaning. If the idiom is “transparent,” we rarely think about its literal meaning. When you say “It’s raining cats and dogs,” you probably don’t picture cats and dogs falling from the sky (at least not very often). This is even more true of opaque idioms that don’t lend themselves to any corresponding literal meaning. Those idioms that have stood the test of time had all had to spend time in a linguistic “waiting room.”
Therefore, the transition from a slang phrase to a legitimate idiom is a test of cultural endurance. Most of the terms listed above, like “aura points” or “404 coded,” are currently in that linguistic waiting room. For a phrase to become an idiom, it must shed its original subculture (like gaming or TikTok) and become a “dead metaphor,” a phrase where the speaker no longer thinks about the literal meaning, only the figurative one.
For another example, when we say someone is “letting off steam,” we don’t picture a 19th-century locomotive; the slang survived the technology. In contrast, many modern phrases like “6-7” or “brain rot” are so deeply tied to specific digital habits of 2025 and 2026 that they risk becoming “dated” rather than “idiomatic.” Often, our technology and even culture evolve too quickly for such phrases to survive these sudden changes or shifts in generational trends. These phrases or terms remain slang and may be phased out of use. If such a phrase becomes a universal shorthand for a human emotion or situation, it earns its place in the dictionary.
The Slang Graveyard: Why Some Phrases Fail
Not every viral term has the legs to become a permanent fixture of the English language. Looking back at the 2010s provides a clear view of phrases that were once inescapable but are now considered “cringe” or dated rather than idiomatic:
- “On Fleek”: In 2014, this was the gold standard for describing perfect eyebrows or outfits. However, because it was a “nonsense” word with no root in existing English verbs or nouns, it felt like a fad. Unlike the idiom “dressed to the nines,” which has survived for centuries, “on fleek” lacked the structural utility to last.
- “YOLO” (You Only Live Once): While the sentiment is a classic aphorism, the acronym became a victim of its own popularity. It was used so ironically and aggressively that it burned out. Idioms usually require a slow simmer to integrate into the language, lest they become hackneyed. “YOLO” was a flash in the pan.
- “Fetch”: This slang term fell into the nickname trap. You can’t force people to use your own nickname for yourself, and you can’t force them to use a slang term. Fetch was this rare case; a “manufactured” slang term (from the movie Mean Girls) that people tried to force into the cultural lexicon. It serves as a reminder that for a phrase to become an idiom, its adoption must be organic. As the character Regina George famously said, “Stop trying to make fetch happen,” a line that, ironically, became more of a catchphrase than the slang word itself.
| Term | Era | Status | Reason for Failure/Success |
| “On Fleek” | 2014 | Retired Slang | Too hyper-specific to 2010s aesthetic culture. |
| “Bite the Bullet” | 1800s | Idiom | Descriptive of a universal human experience (endurance). |
| “Lit” | 2010s | Lingering Slang | Has survived longer because it’s a simple metaphor for “fire” or “energy.” |
| “Aura Points” | 2025 | Pending | Its fate depends on whether “Aura” becomes a standard synonym for “reputation.” |
| Term | Era | Status | Reason for Failure/Success |
| “On Fleek” | 2014 | Retired Slang | Too hyper-specific to 2010s aesthetic culture. |
| “Bite the Bullet” | 1800s | Idiom | Descriptive of a universal human experience (endurance). |
| “Lit” | 2010s | Lingering Slang | Has survived longer because it’s a simple metaphor for “fire” or “energy.” |
| “Aura Points” | 2025 | Pending | Its fate depends on whether “Aura” becomes a standard synonym for “reputation.” |
Conclusion: The Survival of the Fittest Phrases
Ultimately, the difference between an idiom and a slang phrase is time and reach. While slang acts as a playground for new ways of speaking, the idiom is the seasoned pro of the language. Most of the viral phrases used in 2026, whether about “aura points” or being “404 coded,” will likely follow the path of “on fleek” and eventually fade into the linguistic background.
However, a rare few will transcend their internet origins. When a phrase becomes so useful that people use it without knowing where it came from, it has officially made the leap. As a writer or communicator, the key is knowing which to use: slang adds immediate, modern flavor to your work, while idioms provide the timeless, reliable structure that ensures your message is understood across generations.
The Final Piece: What About Colloquialisms?
If you are still feeling a bit confused, you aren’t alone. People often use these terms interchangeably, but there is a specific hierarchy. If slang is the “waiting room” and an idiom is the “fixed phrase,” then a colloquialism is the middle ground.
Unlike slang, which is often used to show you belong to a specific subgroup (like “Gen Alpha”), a colloquialism is simply informal, everyday language used by a broad population in a specific region. For example, calling a carbonated drink “pop,” “soda,” or “coke” is colloquial—it’s not a “coded” slang term, but you wouldn’t use it in a formal legal document either.
Because many colloquialisms eventually become fixed phrases, they are the most common ancestors of the idioms we use today. You can explore our full library of colloquialisms to see how these informal regionalisms bridge the gap between temporary slang and permanent idioms.