preview vs showing

preview and showing both are nouns.

Word	Noun	Adjective	Verb	Adverb
preview	Yes	No	Yes	No
showing	Yes	No	No	No

As nouns, showing is a hypernym of preview; that is, showing is a word with a broader meaning than preview:

preview: a screening for a select audience in advance of release for the general public
showing: the display of a motion picture

Other hypernyms of preview include screening, viewing.

preview (noun)	showing (noun)
a screening for a select audience in advance of release for the general public	something shown to the public
an advertisement consisting of short scenes from a motion picture that will appear in the near future	the display of a motion picture

preview (verb)	showing (verb)
watch (a movie or play) before it is released to the general public