making vs film making

making and film making both are nouns.

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

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

Other hyponyms of making include cartography, mapmaking, movie making, moviemaking.

making (noun)	film making (noun)
the act that results in something coming to be	the production of movies
(usually plural) the components needed for making or doing something
an attribute that must be met or complied with and that fits a person for something