grownup grownup /ˈgroʊˌnəp/

adjective

1. (of animals) fully developed  ( big , fully grown , grownup , adult , full-grown , grown )
   (of animals) fully developed
    An adult animal
   an adult animal
    A grown woman
   a grown woman
   

noun

1. () A fully developed person from maturity onward  ( grownup , adult )
   a fully developed person from maturity onward
    As an adult, it's important to take responsibility for your actions
   As an adult, it's important to take responsibility for your actions