feature film vs Western

feature film and Western both are nouns.

Word	Noun	Adjective	Verb	Adverb
feature film	Yes	No	No	No
Western	Yes	No	No	No

As nouns, Western is a hyponym of feature film; that is, Western is a word with a more specific, narrower meaning than feature film:

feature film: the principal (full-length) film in a program at a movie theater
Western: a film about life in the western United States during the period of exploration and development

Other hyponyms of feature film include horse opera.

feature film (noun)	Western (noun)
the principal (full-length) film in a program at a movie theater	a film about life in the western United States during the period of exploration and development