When things grow older or bigger, then "outgrow" the things that used to fit them. For example, children outgrow clothes:
She's outgrowing her clothes every few months it seems like.
A plant can outgrow the place where it's planted:
It'll outgrow that pot soon, so we'll have to transplant it.
You can also outgrow something mentally:
You still play video games? When are you going to outgrow that stuff?