|Noah Webster's Dictionary|
(a.) Capable of being conceived, imagined, or understood.
Conceivable (2 Occurrences)
Luke 13:33 "Yet I must continue my journey to-day and to-morrow and the day following; for it is not conceivable that a Prophet should perish outside of Jerusalem. (WEY)
Romans 5:7 Why, it is scarcely conceivable that any one would die for a simply just man, although for a good and lovable man perhaps some one, here and there, will have the courage even to lay down his life. (WEY)