A word similar to childish, used to
define someone who acts like a kid in most cases. However it does not have to
mean immature but simply acting like someone of a young age, or showing something that relates to a kid.
Examples:
My
girlfriend wanted me to go to the playground with her then go back to her place and eat cookies and
milk to me that just seems kiddish.
The
toy aisle at walmart is very kiddish