Can be confusedchildish childlike (see synonym study at the current entry)
Examples from the Web for childish
We are not "equal" and you are not an ally if this is the childish base of your notions.
The slimy, childish, petulant Viserys starts off as a symbol of everything about Targaryen rule Westeros has rejected.
Why turn a genuine good-news story into an expression of childish pettiness?What Is William and Harry's Problem With The Press?|Tom Sykes|February 14, 2014|DAILY BEAST
The gorgeous sushi chef he meets and falls in love with, Mi-do (Kang Hye-jung), is equally silly and childish.
According to the blog, she soon “backtracked” on her comments, deleting the Facebook thread, and calling the brouhaha “childish.”An Absurd Push for Separation of Religion and State in Canada|Mira Sucharov|November 15, 2013|DAILY BEAST
The most absurd faces, with sprigs of flowers stuck in the oddest fashion in their comical and childish heads!Madame Chrysantheme|Pierre Loti
At times I felt as it were abashed, and even resentful of the various privileges of my childish years.White Nights and Other Stories|Fyodor Dostoevsky
For Berlioz he kept the excited enthusiasm of a child, childish memory doing the trick.The Life of Francis Thompson|Everard Meynell
Had she shown "my puppy" her childish qualities, he would have despised her—he had left that department himself so recently.Hard Cash|Charles Reade
The winning expression of innocence and gentleness in her mild, childish eyes particularly struck him.