What is the meaning of Adieu?

Said to wish a final farewell; goodbye.

A farewell, a goodbye; especially a fond farewell, or a lasting or permanent farewell.

only used in us adieu, second-person plural present indicative of adir-se

inflection of adiar:

1. second-person plural present indicative/subjunctive
2. second-person plural imperative

second-person plural present indicative/subjunctive

second-person plural imperative

farewell, adieu

farewell, adieu

goodbye, see you soon

hello

hello, goodbye

farewell

adieu, goodbye

hello

goodbye

adieu (said to wish a final farewell; goodbye)

Source: wiktionary.org