Search Result for "infantilism": 
Wordnet 3.0

NOUN (2)

1. an abnormal condition in which an older child or adult retains infantile characteristics;

2. infantile behavior in mature persons; 



WordNet (r) 3.0 (2006):

infantilism
    n 1: an abnormal condition in which an older child or adult
         retains infantile characteristics
    2: infantile behavior in mature persons