Short answer: Outdated idioms are phrases most speakers no longer reach for, such as "in a brown study" (lost in gloomy thought), "a pretty kettle of fish" (a mess) and "a stitch in time saves nine." But sounding old is not the same as fading. When we checked Google Books Ngram data on September 28, 2026, several old-sounding idioms, including "hold your horses" and "burning the midnight oil," appeared more often in books from the 2010s than in books from the 1950s. Below, common phrases are sorted into three groups: still fine, dated, and avoid.
How we checked whether an idiom is dated
Most lists of outdated idioms are built on a feeling: this phrase sounds like something a grandparent would say, so it must be dying. That feeling is often wrong, so we used two signals instead of a guess.
The first is the Google Books Ngram Viewer, which counts how often a phrase appears in scanned books. We pulled yearly figures from its English 2019 corpus with no smoothing and averaged three ten-year windows: 1900 to 1909, 1946 to 1955, and 2010 to 2019. The figures in the table are average uses per billion phrases of the same length. They are our own arithmetic from Google's yearly values, so treat them as a trend, not a precise count.
The second signal is a poll. In January 2022, the research firm Perspectus Global published a list of traditional British sayings that people under 50 said they never use. Upworthy's report on it gives the sample as 2,000 people aged 18 to 50. Perspectus runs consumer research that is pitched to the press, and its own page presents this study as a media story, so read the poll as one signal, not a verdict.
Neither source measures speech directly. Books lag behind conversation, and reprints of old novels can keep a phrase alive in print long after people stop saying it. The poll covered British respondents only, while the book data mixes publishing from every English-speaking country.
The outdated idioms table: still fine, dated, avoid
| Idiom | Meaning | Books, 1900s | Books, 1946 to 1955 | Books, 2010s | Verdict | Register |
|---|---|---|---|---|---|---|
| hold your horses | wait, slow down | not pulled | 6.7 | 25.7 | Still fine | Casual |
| burning the midnight oil | working late | not pulled | 13.7 | 26.0 | Still fine | Neutral |
| a fly in the ointment | a small flaw that spoils something | 21.5 | 53.1 | 64.1 | Still fine in writing | Neutral |
| a flash in the pan | a success that does not last | 33.6 | 55.7 | 56.6 | Still fine in writing | Neutral |
| cut the mustard | be good enough | not pulled | 3.3 | 24.6 | Still fine, but slipping | Casual |
| a stitch in time (saves nine) | fix a problem early | 26.9 | not pulled | 11.0 | Dated | Neutral, proverb |
| a pretty kettle of fish | an awkward mess | 14.8 | not pulled | 10.0 | Dated | Casual, jokey |
| in a brown study | lost in gloomy thought | 41.6 | 10.8 | 22.8 | Dated | Literary |
| the bee's knees | excellent | not pulled | not pulled | 2.0 | Dated, playful | Casual |
| gyp | to cheat | not pulled | not pulled | not pulled | Avoid | Offensive |
| Indian giver | someone who takes back a gift | not pulled | not pulled | not pulled | Avoid | Offensive |
"Not pulled" means we did not request that window, not that the count was zero. The verdict and register columns are our guidance, based on the figures, the dictionary labels named below and the poll.
Old-sounding idioms that are still fine
"Hold your horses" refers to a world of carriages and reins, yet in the Ngram data it appeared almost four times as often in 2010s books as in books from 1946 to 1955. "Burning the midnight oil" refers to lamps nobody uses, and it roughly doubled over the same span. An idiom does not need its original object to survive. People keep the picture long after the thing is gone.
"A fly in the ointment" and "a flash in the pan" show the gap between print and speech most clearly. In books, both grew across the century. In the Perspectus poll, 59 percent of respondents under 50 said they never use "a fly in the ointment," and 57 percent said the same of "a flash in the pan." Both statements can be true: a phrase can be common in newspapers and novels and rare in conversation among younger speakers. For writing, both are safe. In speech, they may mark you as bookish, which is not always a bad thing.
"Cut the mustard" is the one to watch. It grew strongly after the 1950s, but within the 2010s its yearly figure fell from about 30 per billion in 2010 to about 18 in 2019. That is a real dip, though too short to call a decline.
Idioms that really are fading
"In a brown study" is the clearest case. Wiktionary's entry for "brown study," which we read on September 28, 2026, labels it dated, explains that "brown" here is an obsolete word for gloomy, and quotes John Dryden's play Amphitryon (1690): "What, in a brown Study?" In the Ngram data, it fell by roughly three quarters between the 1900s and the years around 1950.
It then appears to recover in the 2010s, but look closer and nearly all of that rise sits in 2017 to 2019. "A pretty kettle of fish" jumps in the same years. When several old phrases rise together at the very end of a corpus, a change in what was scanned is at least as likely as a revival in speech. We cannot tell which from the data, so we have not counted the jump as a comeback.
"A pretty kettle of fish" means an awkward mess. Wiktionary traces "kettle" here to "kiddle," a fence of stakes set in a stream to catch fish, and lists "fine kettle of fish" as the other common form. In books, it slid from about 14.8 per billion in the 1900s to about 10.0 in the 2010s.
"A stitch in time saves nine" is still understood, but it is losing ground. Its shorter form, "a stitch in time," fell from about 26.9 per billion in the 1900s to about 11.0 in the 2010s, and in the Perspectus poll 64 percent of under-50s said they never use the full proverb. It now reads as something a parent says, which is fine if that is the effect you want.
"The bee's knees" turns up about twice per billion phrases in 2010s books, low enough that using it sounds deliberately old-fashioned. That can be charming in a casual blog post and odd in a work email.
Idioms to avoid, whatever their age
Some phrases should go not because they are old but because a dictionary now flags them as offensive. These are in a different category from "dated": the problem is not that readers find them quaint, it is that some readers find them insulting.
Gyp (to cheat). Wiktionary's entry for "gyp," read on September 28, 2026, labels the verb "derogatory, sometimes offensive." It notes the word is often considered to come from "Gypsy" and to represent a racist stereotype of the Romani people. Say "cheated" or "overcharged" instead.
Indian giver. Wiktionary defines it as a person who takes back something they gave, and labels it informal and now offensive. Describe the action plainly instead: "he took back the gift."
Region does not rescue either phrase. If a reader anywhere could take the words as a slur, a neutral wording costs you nothing.
The opposite problem: new idioms that are everywhere
The same data shows where the energy in English idioms went. "The elephant in the room," "think outside the box" and "low-hanging fruit" were close to zero in books from 1946 to 1955. In 2010s books they averaged about 120, 147 and 74 per billion, well above every older phrase in the table.
These are not dated. They are the opposite: so common in business writing that many readers now treat them as cliches. If you are pruning tired phrases from a draft, these may deserve the cut more than "hold your horses" does. Our guide to commonly misused idioms covers a related trap, where a phrase is used so often that its wording drifts.
How to tell whether an idiom sounds dated to your reader
- Check a dictionary label. Words like "dated," "old-fashioned" or "archaic" are the dictionary telling you the phrase is fading. "Offensive" or "derogatory" is a stronger warning.
- Check the trend, not a single year. A phrase that has held steady in print for a century is not dying, however old its image.
- Think about who is reading. A phrase can be familiar to older readers and unused by younger ones, as the poll suggests for "a fly in the ointment."
- For learners, prefer the plain word. A non-native reader may know "it did not last" but not "a flash in the pan."
- Look at where the phrase came from. Knowing the history helps you judge whether the image still lands. Our explainer on how a phrase origin is traced shows how references date a phrase.
Some old phrases survive by shrinking. "The proof is in the pudding" is itself a cut-down version of a longer sentence, as our page on the 1605 sentence it was cut from explains. Shortening is often how an idiom stays alive rather than a sign it is dying.
Frequently asked questions
What are some examples of outdated idioms?
"In a brown study," "a pretty kettle of fish," "the bee's knees" and, increasingly, "a stitch in time saves nine." Wiktionary labels "brown study" dated, and the others appear far less often in 2010s books than older favorites that are still going strong.
Is "burning the midnight oil" outdated?
No. Its image is old, but in Google Books data it appeared about twice as often in the 2010s as in the years around 1950. It is still a neutral, widely understood way to say you worked late.
Is it wrong to use an old-fashioned idiom?
No. A dated idiom is not an error. It simply signals a tone: playful, bookish or old-fashioned. Use it when you want that tone, and choose plain words in a formal email or when writing for English learners.
How can I check whether an idiom is still used?
Look for a "dated" or "archaic" label in a dictionary, then compare the phrase's trend in the Google Books Ngram Viewer over several decades. Remember that both measure writing, not speech.
Which old idioms should I stop using?
Drop phrases a dictionary labels offensive, such as "gyp" and "Indian giver," whatever their age. Merely dated phrases are a style choice, not a mistake.
