A few dictionary definitions include:
- From Cambridge Dictionary - actions and behavior that are considered typical of adults, not children or young people
- From Dictionary.com - Adulting is an informal term to describe behavior that is seen as responsible and grown-up. This behavior often involves meeting the mundane demands of independent and professional living, such as paying bills and running errands.
- From Merriam-Webster - The verb 'adulting' is all grown up.