la–la land 
/ˈlɑ:ˌlɑ:-/ noun
/ˈlɑ:ˌlɑ:-/ noun [noncount] informal 1 : the mental state of someone who is not aware of what is really happening — usually used in the phrase in la-la land ▪ I tried to talk to him, but he was off in la-la land. ▪ If that's what she thinks, she's living in la-la land. —called also (Brit) cloud-cuckoo-land 2 La-La Land — used as a nickname for Los Angeles, California ▪ stories about life in La-La Land
