Bye-bye and Bye bye

Bye-bye noun - A farewell remark.

Bye bye and bye-bye are semantically related In some cases you can use "Bye bye" instead the phrase "Bye-bye" as a noun or a interjection.

Bye-bye and bye bye are semantically related in departure topic. You can use "Bye-bye" instead the phrase "Bye bye" as a noun or a interjection, if it concerns topics such as goodbye, farewell statement, have a nice trip.