It is entirely inerrant and sufficient for all Christian life. An aberrant doctrine is a teaching that is different than anything other than the core doctrines of Christianity, and which is based on a non orthodox interpretation of Scripture. This is what apologetics is all about, which is a good and healthy exercise in any religious system. As defined above an aberrant doctrine is a doctrine that differs from the historical orthodox biblical Christian doctrinal stance. The goal of definitions is to keep any religious system doctrinally pure and without any potentially destructive influences from other belief systems being taught that would tend to degrade or nullify the core beliefs of that religion.
Some religions are open to change from without and that is their right and choice.
Other religions, such as biblical Christianity, Judaism and Islam have been historically not open to doctrinal change and that is also their right and choice. Biblical Christianity has a doctrinal system that is based on the sixty-six books of the Bible, and this is a Christian's highest authority in all matters of faith and practice. People are free to call themselves anything they want, but religions such as Christianity have core doctrines they hold to. It is also possible for a person or group to be a cult and also have aberrant doctrines. If a person or group is aberrant and begins to teach against the core doctrines of Christianity, they need no longer be called aberrant because they have become a cult of Christianity.