goodbye

good|bye1 [ gud`baı ] interjection *

used when you are leaving someone or when someone is leaving you, or when you are finishing a telephone call. Bye is a more informal word and is a more common way of saying goodbye to a friend or to someone you know well:

Goodbye, Mr. Taylor. Goodbye, John.

(it's) goodbye (to) something (and) hello (to) something INFORMAL

used for saying that one activity or period has ended and another one has started

goodbye

good|bye 2 [ gud`baı ] noun count *

any word or phrase you say when you leave someone or when someone leaves you:

Emma left without even a goodbye.

say your goodbyes: It was heartbreaking saying our goodbyes at the airport.

a. kiss someone goodbye to kiss someone when you leave them or as they leave you

b. say goodbye (to someone) to use a word or phrase such as goodbye or see you when you leave someone or when someone leaves you

c. wave goodbye (to someone) to wave your hand when you leave someone or as they leave you

say/wave/kiss goodbye to something

to accept that you will not achieve, get, or keep something