Purist (noun)

1. A person who insists on absolute adherence to traditional rules or structures, often to an excessive or obsessive degree.
2. A person who advocates for purity, especially in language or art.

Origin:

From french puriste, from pur ('pure').

Examples:

1. The language purist criticized the use of slang words in the newspaper.
2. The art purist refused to consider any modern art as true art.
3. The music purist only listened to classical music and criticized pop music.
4. The purist argued that the recipe should only include the original ingredients.
5. The literary purist insisted that the author's original manuscript should not be changed.