A person past middle age, perhaps (but not necessarily) elderly. Now that I'm an older adult, I have all these aches and pains that I never felt before. You don't have to speak loudly to them, you know—not all older adults have trouble hearing.

slang The (sometimes daunting) task of acting mature and responsible. Usually used humorously by young adults. Does this mean I have to cook for myself now? I hate adulting. Adulting is the worst—as soon as I get paid, the money goes directly to bills.

verb To act mature and responsible. This slang term is typically used humorously by young adults. Ugh, I can't adult today—I'm going back to bed.

An oafish man prone to rambunctious behavior, despite having reached adulthood. The frequent subject of memes, the phrase is often linked to a family photo of American politician Mike Huckabee that includes his two literally large adult sons. Despite being 35 years old, my son is such a doofus. I can't believe I have a large adult son. My large adult sons just gave our dog a bath in the trunk of my car.