A Barrack Room Lawyer is a disparaging term for a person, meaning they are unqualified or inexperienced at what they are attempting to achieve – usually in professional circles. Since the 1800s, the Queen's or King's Regulations have allowed soldiers without any formal legal training to conduct their own defence, promote their own interests or make a formal complaint to superiors. But those who did so were very usually held in contempt by their commanding officers, who conferred the uncomplimentary tag upon them. The expression had passed into common usage by the beginning of the 20th century and is still here to this day.