play-act       
verb [ I or T ] uk/ˈpleɪ.ækt/ us/ˈpleɪ.ækt/
 假装;演戏
to hide your feelings from other people, or to entertain them, by deliberately behaving in a way that does not represent your true feelings
  He knew she wasn't play-acting. 他知道她不是在演戏。 
 Children sometimes play-act their idea of what an adult might do. 孩子们有时会表演他们所认为的成人的做法。 
 See: play-acting
 - More examples
 - You don't have to play-act anymore.
 - Dominic had spent the last two months play-acting and tonight had decided to drop the façade.
 - It was no good, she couldn't play-act indifference any longer.