To abandon, “to go back on.”

1

1862.  Guess the M.P. will “sour” on William C., when he has seen him for about fifteen minutes.—Rocky Mountain News, Denver, Nov. 20.

2

1863.  Several of the boys about town talk of turning over a new leaf. Their programme is to “sour” on smoking, chewing, and drinking.—Id., Jan. 1.

3