noun
Usage: sometimes capitalized J & usually capitalized M
1. : a non-Mormon living in a Mormon community and sympathetic to or on friendly terms with his neighbors
2. : a Mormon inactive in the church or not adhering strictly to Mormon tenets : a backsliding or nominal Mormon
always paid his tithes — only he had to have his coffee so some called him a jack Mormon — American Guide Series: Arizona
a jack Mormon, which means that … he no longer pays tithes or holds with the tenet of total abstinence — A.J.Liebling