1
: fully developed and mature : grown-up
an adult lion
2
: of, relating to, intended for, or befitting adults
an adult approach to a problem
3
: dealing in or with explicitly sexual material
adult bookstores
adult movies
adulthood noun
adultly
ə-ˈdəlt-lē How to pronounce adult (audio)
ˈa-ˌdəlt-
adverb
adultness
ə-ˈdəlt-nəs How to pronounce adult (audio)
ˈa-ˌdəlt-
noun

adult

2 of 3

noun

: one that is adult
especially : a human being after an age (such as 21) specified by law
adultlike adjective

adult

3 of 3

verb

adulted; adulting; adults

intransitive verb

1
informal : to behave like an adult : to attend to the ordinary tasks required of a responsible adult
Do we really have to adult today?Lauren Merola
Stop complaining that you have to adult today. Being an adult is awesome.Suzanne Lucas
Learning how to "adult" is a necessity for these college freshmen in order to figure out new medication schedules and if their parents' insurance will cover impromptu ER visits.Meredith Newman
2
informal : to become an adult
It could be something small, like bailing on your friends at the last second. Or something bigger, like not showing up for work. Whatever the case may be, it's a sign you haven't fully "adulted" if you constantly slack off on your responsibilities.Carolyn Steber
But there is one real benefit to growing older and adulting: We essentially get to do whatever we want to do.Sharon Pope

Examples of adult in a Sentence

Adjective preparing children for adult life We need to approach this in an adult way. Noun Her books appeal both to children and to adults. Children must be accompanied by an adult in the museum. Only adults can purchase alcohol. This film is for adults only. Minors are not admitted. People who are close friends as children aren't always friends as adults. studying interactions between young birds and adults See More
Recent Examples on the Web
Adjective
Over a period of more than 2,500 hours of observation at three sites – Southeast Farallon Island, Año Nuevo Island and Tomales Point – scientists identified nearly 300 adult and sub-adult individual great whites. Julia Musto, Fox News, 26 May 2021 There has not been a sighting of a calf since 2005, though juvenile and sub-adult whales have been seen more recently, Crance said. Tara Duggan, San Francisco Chronicle, 6 Mar. 2023 The first whale found this month, a sub-adult male gray whale, was recovered Jan. 11 in Winchester Bay and was slain by killer whales, according to Milstein. oregonlive, 24 Jan. 2023 There wasn’t much room for making mistakes in this version of adulting—which is, of course, the only way to become truly adult. Claire Cohen, Vogue, 15 Jan. 2023 There was probably no better example Monday night than Quinta Brunson having to deliver her polished and very adult speech while standing over Jimmy Kimmel, who was lying on the stage as part of a dumb bit and wouldn’t get up. Mike Hale, New York Times, 12 Sep. 2022 According to the Cleveland Clinic, water is essential for multiple functions in your body, including digestion, creating hormones and neurotransmitters, and delivering oxygen, and up to 60 percent of the adult human body is made of water. Laura Baisas, Popular Science, 3 Jan. 2023 Children faced truancy charges in adult criminal courts, often with no legal representation. Dallas News, 23 June 2022 Phifer’s brother, Terrence Banks, adopted an adult German shepherd named Chance. La Risa R. Lynch, Journal Sentinel, 20 Dec. 2022
Noun
All of them, virtually without exception, are fundamentally selfish and do not respect adult boundaries or adult perspectives. Ej Dickson, Rolling Stone, 28 Nov. 2023 In our testing, there was plenty of floor space for two adults, two toddlers, and a large-ish dog. Scott Gilbertson, WIRED, 27 Nov. 2023 The Pueblo County Sheriff’s Office said in a news release that the unidentified family, consisting of two adults and three children, were out on a hike in the Greenhorn Trailhead in the morning and were approaching the summit when they were stymied by the altitude and unexpected snow. David Chiu, Peoplemag, 27 Nov. 2023 The young adults of the 2030s may recall it fondly. Robert Lloyd, Los Angeles Times, 27 Nov. 2023 Save on adult charm bracelets from indie brand Oak & Luna, custom name necklaces under $25, and so much more. Jake Smith, Glamour, 27 Nov. 2023 In court, he was charged as an adult with four counts of aggravated murder. Jennifer Gonnerman, The New Yorker, 27 Nov. 2023 The ceremony earned a 4.0 rating in the adults 18-49 key demo, pushing it to three-year highs in both total viewers and demo — up 5% since 2020. Variety, NBC News, 15 Nov. 2023 Nevada judges can certify minors older than 14 as adults for felony offenses, including murder, but that’s not a given. Timothy Bella, Washington Post, 15 Nov. 2023
Verb
In a recent paper published in the journal eLife, Truman’s team tracked how the neural connections were altered in the transition from Drosophila larva to adult—what was remodelled, what was destroyed, what was generated anew. Rivka Galchen, The New Yorker, 31 Aug. 2023 Natural Discoveries Join a group ages 7 to adult for an easy walk to observe the unfolding of nature from 10 to 11 a.m. Jan. 12 at Princess Ledges Nature Preserve, 4361 Spruce Ave. Mary Jane Brewer, cleveland, 3 Jan. 2022 The Phoenix Zoo is bringing back its Roars & Pours adult social gathering after 18 months of it being discontinued during the pandemic. Shanti Lerner, The Arizona Republic, 13 Nov. 2021 Season two will introduce viewers to adult Lottie, as Simone Kessell (Obi-Wan Kenobi, Our Flag Means Death) has been cast in the role. Jackie Strause, The Hollywood Reporter, 22 Mar. 2023 The Botas Attack 181 come in a wide variety of sizes, from children to adult, and offer durable, reliable construction for first-timers. Popular Science, 4 Mar. 2021 Keck noted a housefly can go from egg to adult in about a week. René A. Guzman, ExpressNews.com, 9 Dec. 2020 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'adult.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Adjective

borrowed from French & Latin; French adulte, going back to Middle French, borrowed from Latin adultus, from past participle of adolēscere, adulēscere "to become mature, grow up," from ad- ad- + alēscere "to be nourished, grow up," probably inchoative derivative of *alēre "to grow," stative derivative of alere "to nurse, feed, nourish" — more at old entry 1

Noun

derivative of adult entry 1

First Known Use

Adjective

1531, in the meaning defined at sense 1

Noun

1655, in the meaning defined above

Verb

1909, in the meaning defined at sense 2

Time Traveler
The first known use of adult was in 1531

Dictionary Entries Near adult

Cite this Entry

“Adult.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/adult. Accessed 3 Dec. 2023.

Kids Definition

adult

1 of 2 adjective
1
: fully developed and mature
2
: of, relating to, or characteristic of adults
adulthood noun
adultness
ə-ˈdəlt-nəs How to pronounce adult (audio)
ˈad-ˌəlt-
noun

adult

2 of 2 noun
: a fully grown person, animal, or plant
adultlike adjective
Etymology

Adjective

from Latin adultus "having grown up," from adolescere "to grow up" — related to adolescence

Medical Definition

adult

1 of 2 adjective
: fully developed and mature

adult

2 of 2 noun
1
: one that has arrived at full development or maturity especially in size, strength, or intellectual capacity
2
: a human male or female after a specific age (as 18 or 21)

Legal Definition

adult

noun
: a person who has reached an age specified by law compare child, infant, minor

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