bye–bye 
/ˈbaɪˌbaɪ/ interjection
/ˈbaɪˌbaɪ/ interjection informal : 1goodbye
▪ Bye-bye! See you later! — often used by children or when speaking to children ▪ Say/Wave bye-bye, darling: it's time to go home.
▪ Bye-bye! See you later! — often used by children or when speaking to children ▪ Say/Wave bye-bye, darling: it's time to go home.
go bye-bye
informal 1 or Brit go bye-byes : to go to bed — used when speaking to children ▪ It's time to go bye-bye, darling: it's way past your bedtime! 2 US : to go away — used in imitation of children's speech ▪ When the company went bankrupt, investors watched their money go bye-bye.
