It’s “kidult”:

While many people in their forties have families and responsibilities, an increasing minority still resemble teenagers. Scary, wrinkled, grey-haired teenagers, with some kind of terrifying premature ageing disease, but teenagers nonetheless. It’s enough of a phenomenon to have been given its own portmanteau label: kidult.

According to the piece, it’s hard to remain a kidult if you have kids yourself. But false modesty aside, I think I’ve managed.

HT: Kerry Howley