infantilism

English Thesaurus

1. infantile behavior in mature persons (noun.act)

hypernym	:	misbehavior, misbehaviour, misdeed,
definition	:	improper or wicked or immoral behavior (noun.act)

2. an abnormal condition in which an older child or adult retains infantile characteristics (noun.state)

hypernym	:	abnormalcy, abnormality,
definition	:	an abnormal physical condition resulting from defective genes or developmental deficiencies (noun.state)

hyponym	:	ateleiosis, ateliosis,
definition	:	a form of infantilism characterized by physical underdevelopment but normal intelligence (noun.state)