thirtysomethingnoun [ C ]
uk/ˈθɜːtiˌsʌmθɪŋ/usinformala person between 30 and 39 years old:
They aimed their campaign at affluent thirtysomethings.
thirtysomething
adjective [ before noun ]
The ads target upmarket thirtysomething wine drinkers.
Compare
twentysomething