Entry 2 senses · 2 variants Webster, 1913 Adieu /əd-o͞o'/ · A·dieu · IPA /əˈdju/ interj. & adv. n. 01 interj. & adv. Good-by; farewell; an expression of kind wishes at parting. 1. Good-by; farewell; an expression of kind wishes at parting. 02 n. A farewell; commendation to the care of God at parting. pl. Adieus 1. A farewell; commendation to the care of God at parting.