General terms:
* Documentary - This is the most common synonym for a factual film, referring to a non-fiction film that aims to inform or educate the audience.
* Non-fiction film - This is a broader term that encompasses documentaries as well as other types of factual films, such as newsreels or instructional videos.
* Real-life film - This emphasizes the fact that the film is based on real events and people.
More specific terms:
* Exposé - A film that reveals or exposes wrongdoing or corruption.
* Historical film - A film that tells a story based on historical events.
* Biographical film - A film about the life of a real person.
* Nature documentary - A documentary that focuses on the natural world.
* Scientific documentary - A documentary that explores scientific topics.
The best word to use will depend on the specific type of factual film you are describing. It's also helpful to consider the context of your writing and the specific audience you are addressing.