In German the verb for “to grow up” is “aufwachsen” (pronunciation: “owfvaxen”). It can not be used in the imperative (i.e. one can not tell someone to “grow up” in German). The word for “grown-up” (in the sense of “adult”) is “erwachsen” (pronunciation: airvaxen):

– “Ich bin in Amerika aufgewachsen.” – “I grew up in America.”
– “Er soll so nicht aufwachsen.” – “He should not grow up like that.”
– “Er ist jetzt ein erwachsener Mann.” – “He is now a grown-up man.”

On a related note, the word for “to raise” (in the sense of rearing, nurturing or bringing up children) is “erziehen”:

“Die Mutter erzieht jetzt das Kind.” – “The mother is raising the child now.”