thirtysomething
noun [ C ]
informal uk/ˈθɜːtiˌsʌmθɪŋ/ usa 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