hardshell Baptist; hard-shell Baptist noun a member of the Primitive Baptist Church, or any other rigidly orthodox Baptist US,1838
Bill Hill’s ex-wife, Barbararose, who was a hard-shell Baptist out of Nashville, where there were 686 different Fundamentalist churches, had called the whole Uni-Faith setup “a mockery in the eyes of God.” — Elmore Leonard, Touch, p. 90, 1977