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
: one that is adult
especially
: a human being after an age (such as 21) specified by law
adulted; adulting; adults
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
Lauren MerolaStop complaining that you have to adult today. Being an adult is awesome.—Suzanne Lucas
Suzanne LucasLearning 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
Meredith Newman2
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
Carolyn SteberBut there is one real benefit to growing older and adulting: We essentially get to do whatever we want to do.—Sharon Pope
Sharon PopeExamples 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
Recent Examples on the Web
Jenna Prestininzi, Freep.com, 21 Oct. 2025
The Melon Patch also incorporates puppets to bring in a non-adult character who relates to kids.
—Elisabeth Sherman, Parents, 23 Sep. 2025
Joni Eareckson Tada, MSNBC Newsweek, 25 Oct. 2025
Put together a few games for the kids, or set up a spooky drink cart for an adults-only get-together.
—Kylie Petty, Better Homes & Gardens, 25 Oct. 2025
Literary Hub, 17 Oct. 2025
The face, more squarely adult now, has a certitude in the jaw and an impatience in the eyes.
—Nathan Heller, Vogue, 14 Oct. 2025
See All Example Sentences for adult
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Adjective
Tickets are $10 for non-adult guests, free for hotel guests and non-guest children under age 12, with proceeds benefiting Give Kids the World, a nonprofit resort providing vacations to ill children and their families.
—Jenna Prestininzi, Freep.com, 21 Oct. 2025
The Melon Patch also incorporates puppets to bring in a non-adult character who relates to kids.
—Elisabeth Sherman, Parents, 23 Sep. 2025
Noun
Nearly 40 percent of adults with disabilities feel isolated.
—Joni Eareckson Tada, MSNBC Newsweek, 25 Oct. 2025
Put together a few games for the kids, or set up a spooky drink cart for an adults-only get-together.
—Kylie Petty, Better Homes & Gardens, 25 Oct. 2025
Verb
Dust that is drawn to adult humans and lights up a mysterious city from another world lying just beyond the Northern Lights.
—Literary Hub, 17 Oct. 2025
The face, more squarely adult now, has a certitude in the jaw and an impatience in the eyes.
—Nathan Heller, Vogue, 14 Oct. 2025
See All Example Sentences for adult
Cite this Entry
“Adult.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/adult. Accessed 30 Oct. 2025.
Copy CitationKids Definition
1
: fully developed and mature
2
: of, relating to, or characteristic of adults
Etymology
Adjective
from Latin adultus "having grown up," from adolescere "to grow up" — related to adolescence
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