This is how my Macbook defines it
infantilize |ˈinfəntlˌīz, inˈfan-| verb [ withobj. ]treat (someone) as a child or in a way that denies their maturity in age or experience:seeing yourself as a victim infantilizes you.
Here is a video link:
https://www.youtube.com/watch?v=yJGGZS04Uus