A more thorough explanation:

A special pleader is a person who specializes in preparing pleadings for others in court. They are not necessarily an attorney, but they have expertise in crafting legal arguments and presenting them effectively.

For example, in the past, a person who wanted to bring a lawsuit would hire a special pleader to draft their complaint and other legal documents. The special pleader would use their knowledge of the law and court procedures to create a persuasive argument that would be presented to the judge.

Today, the role of the special pleader has largely been taken over by attorneys, who are trained in both legal theory and practical advocacy. However, the term may still be used in some contexts to refer to someone who specializes in drafting legal documents.