SOUR

sour: (1) bocer, "immature," "unripe": "The fathers have eaten sour grapes" (Jeremiah 31:29 f; Ezekiel 18:2; compare Isaiah 18:5 the King James Version). (2) cur, "to turn aside," "degenerate": "Their drink is turned sour" (the King James Version margin "gone," the Revised Version margin "Their carouse is over").

From the International Standard Bible Encyclopedia
Edited by James Orr, published in 1939 by Wm. B. Eerdmans Publishing Co.