'Good-by' definitions:

Definition of 'good-by'

(from WordNet)
noun
A farewell remark; "they said their good-byes" [syn: adieu, adios, arrivederci, auf wiedersehen, au revoir, bye, bye-bye, cheerio, good-by, goodby, good-bye, goodbye, good day, sayonara, so long]

Definition of 'Good-by'

From: GCIDE
  • Good-by \Good`-by"\, Good-bye \Good`-bye"\, n. or interj. [A contraction of God be with ye (God be w[i^] ye, God bw' ye, God bwye).] Farewell; a form of address used at parting. See the last Note under By, prep. --Shak. [1913 Webster]