special pleader
/ˌspɛʃl ˈpliːdə/noun
1 Law. A member of an Inn of Court who specializes in drawing pleadings. Also figurative. Now historical.
2A person who uses one-sided argumentation; a disingenuous or sophistical disputant.
Origin
Early 18th century. From special + pleader, after special-plead, special pleading.