GROW UP

v. 1. To increase in size or height; become taller or older; reach full height. Johnny is growing up; his shoes are too small for him. I grew up on a farm. The city has grown up since I was young. 2. To become adult in mind or judgment; become old enough to think or decide in important matters. Tom wants to he a coach when he grows up. Grow up, you're not a baby any more!