I define "unscriputral" as being opposed to, or not corresponding with, what is taught in Scripture (which, perhaps, is "anti" rather than "un"). Jesus suffered in Hell for our sins (Joyce Meyers doctrine) is un (anti) biblical. Baptismal regeneration is an un (anti) biblical doctrine. Both of these examples deny what Scripture teaches (they are opposed to what is taught in the Bible).
Most of us old baptists are just agin it what ever it is. We are crotchety, and agin any thing new, different and anything which requires much thought.
What is scriptural? That is thorny, nebulous and opinionated. Even Plato would not touch that question.
My answer is any interpretation which agrees with me. LOL