infantilism
noun/ɪnˈfæntɪlɪzəm/
/ɪnˈfæntɪlɪzəm/
[uncountable]- (disapproving) silly behaviour that is typical of a child and not suitable in an adult
- the trivial infantilism of commercial movies
- (psychology) the fact of adults continuing to behave like children, in a way that is not usual
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infantilism