apologist

noun apologist

• pleader — a person who pleads, especially at law.
• polemicist — a person who is engaged or versed in polemics.
• sophist — (often initial capital letter) Greek History. any of a class of professional teachers in ancient Greece who gave instruction in various fields, as in general culture, rhetoric, politics, or disputation. a person belonging to this class at a later period who, while professing to teach skill in reasoning, concerned himself with ingenuity and specious effectiveness rather than soundness of argument.
• adherent — An adherent is someone who holds a particular belief or supports a particular person or group.
• advocate — If you advocate a particular action or plan, you recommend it publicly.