Adult

Signing: To sign adult you start with your dominant hand fingers outstretched, palm facing down at shoulder height. Move your palm upwards until it is above your head.

The sign looks like you are illustrating the growth of a child into an adult.

Usage: You can use adult to refer to grownups. As a contrast, you can also teach the words baby, or for older children boy and girl.

You could say something like, “Daddy is an adult & Jenny is a baby.”