A Jack Mormon is a Mormon, either by conversion or upbringing, who doesn’t adhere to the teachings of the LDS faith for whatever reason.
**** Sometime between then and now, “Jack Mormon” was transformed in popular usage from a non-Mormon who was friendly to Mormons, to a Mormon who is way too casual with regard to his church’s values. ****
Anything like a Jack Catholic? A Protestant (or other) Anglo who went to Texas and converted to Catholicism so he could get land before the revolution of 1836?