Also see definition of "Sour" in Word Study
Sour
SOUR [isbe]
SOUR - sour: (1) bocer, "immature," "unripe": "The fathers have eaten sour grapes" (Jer 31:29 f; Ezek 18:2; compare Isa 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").
Also see definition of "Sour" in Word Study
