Sentence:  I mean something more like Freud 's concept of the utility of `` play '' to a <WSD>small</WSD> child : he plays `` house '' or `` doctor '' or `` fireman '' as a way of mastering slightly frightening experiences , reliving them imaginatively until they are under control . 
Meaning of the word marked with <WSD> tags:  (of children and animals) young, immature