If you haven't heard it (or don't use it) already, you'll hear it soon: adult as a verb, as in "Someone please teach me how to adult."
It's also common as a gerund—that is, in the form adulting as a noun, as in "Adulting is hard" or "I’m not very good at adulting."
To adult is to behave like an adult, to do the things that adults regularly have to do. This includes things like having a job and living independently, sure, but also such mundanities as taking clothes to the dry cleaners (and remembering to pick them up), making and keeping dental appointments, getting your car registered, doing yardwork.
It's not a serious word, but it's increasingly used in published, edited text, and it keeps showing up in ad copy, which is a certain sign of some kind of linguistic arrival.
The first five months of 2016 have seen a 6-fold increase in use over last year in the Lexis-Nexis database of publications, and Digiday reports that Brandwatch has seen mention of adulting "642,000 times online in the last year, with usages peaking last month with more than 87,000 mentions." Advertisers are jumping on the adulting train: "Brandwatch found that brands from finance (Credit Karma, TD Ameritrade) to retail (Target, Amazon) to food (Fruity Pebbles cereal) have all used it."
If we go back to the infancy of the verb adult, though, we find another meaning entirely: as a jocular verbal form of the noun adultery—in other words, as a synonym of to commit adultery:
It seems 25 years ago Torn was wed to Miss Page and Higgins to Miss Harris. Then Torn took up with Miss Harris and Higgins took up with Miss Page. Or vice versa. Then all four adulterers divorced their spouses and married those with whom they'd been adulting. — Jay Sharbutt, The Associated Press, 28 Dec. 1980
Almost 20 years later, the gerund was being used by the author of Chicken Soup for the Soul at Work, Martin Rutte, who talked about "the adulting of the workplace," by which he meant "that employees are growing up to see that the company doesn't provide security" (Martin Rutte, quoted in The Hamilton Spectator [Ontario, Canada], 23 May 1998).
A decade later, this:
... a boutique movie theatre with wide, wide sofa seats and refreshments served direct to the auditorium. Clearly it's part of the modern fad for what we might call the adulting of cinemagoing—along with no-kids screenings and the Smoking Cabinet series. —Andrew Pulver, The Guardian, 22 Dec. 2008
None of these matches the current use. Something much closer to what we're hearing now first appeared on Twitter in 2008 and 2009:
@ditzyAzian Why thank you for the compliment. Alas! I was kidding as well. In fact, I can honestly say I was adulting. Chihihi! X]
— al.drin (@___aldrin___) December 29, 2008cannot possibly be an adulterer. barely knows how to adult.
— Kathryn Borel Jr. (@kathrynborel) October 13, 2009
In the first example, the word is contrasted with kidding, and the meaning of adulting isn't at all clear. In the second, there's again an allusion to adultery, but the meaning is clearly the one we're seeing now.
Another early Twitter example shows the word being used self-consciously, as demonstrated by the punctuation used:
LMAO WE'RE THINKING TAILORED SUITS RT @dollymiiix LMFAO @OMGELVIS AND I ARE DISCUSSING HOW TO ~ADULT~ UP OUR LOOK BECAUSE WE DRESS LIKE KIDS
— Colt(as)45. (@omgelvis) November 9, 2009
In 2010, we started seeing examples more typical of current use:
https://twitter.com/TheClassicEarl/status/7645995975
Some, though, learned the verb adult from a popular 2013 book by journalist Kelly Williams Brown. The book is called Adulting: How to Become a Grown-Up in 468 Easy(ish) Steps, and it's a how-to for millennials trying to function as autonomous adults. It was preceded by a popular blog called Adulting, which Brown started in 2011.
Others learned the word when Grammar Girl named adulting her Word of the Year in 2014. Grammar Girl interviewed Brown, who said she had not been aware of the word before she started using it.
And so we have a word that has been weakly crawling along for decades emerging slowly into something akin to a full-fledged member of the language. We'll be watching to see if it stands on two legs long enough for us to consider it fully established, but in the meanwhile, congratulations, adult, on your recent adulting.
Update: This word was added in September 2023.
Words We're Watching talks about words we are increasingly seeing in use but that have not yet met our criteria for entry.