improv       
noun [ C or U ] uk/ˈɪm.prɒv/ us/ˈɪm.prɑːv/
 即兴乐;即兴表演;即兴剧
a performance, for example of comedy or acting, that is improvised (= invented as it is done rather than using words or music written and practised in advance)
  The show mixes scripted satire with improv. 该节目将准备好剧本的讽刺内容与即兴表演混合在一起。 
 I saw him do an improv at a comedy festival.  我在喜剧节上看过他的即兴剧。 
 She started out with an improv theatre group. 她的演艺生涯从一个即兴剧团开始。 
 - More examples
 - Improv is usually either really good or really terrible.
 - He did a bit of jazz improv.
 - A few people walked out and then someone said "It's an improv".
 - He decided to have the actors do an improv in public as their characters.