documentary vs documentary film

documentary and documentary film both are nouns.

Word	Noun	Adjective	Verb	Adverb
documentary	Yes	Yes	No	No
documentary film	Yes	No	No	No

As nouns, documentary and documentary film are synonyms defined as:

documentary and documentary film: a film or TV program presenting the facts about a person or event

Other synonyms of documentary include docudrama, infotainment.

documentary (noun)	documentary film (noun)
a film or TV program presenting the facts about a person or event	a film or TV program presenting the facts about a person or event

documentary (adjective)	documentary film (adjective)
relating to or consisting of or derived from documents
(of film, television, radio, or photography) depicting a real-life event using images or interviews with people involved in the event