1.
Something or someone that is ~ is not yet completely grown or fully developed.
She is emotionally ~.
ADJ
immaturity
In spite of some immaturity in the figure drawing and painting, it showed real imagination.
N-UNCOUNT
2.
If you describe someone as ~, you are being critical of them because they do not behave in a sensible or responsible way.
She’s just being childish and ~.
ADJ disapproval
immaturity
...his immaturity and lack of social skills.
N-UNCOUNT