legal action vs proceeding

legal action and proceeding both are nouns.

Word	Noun	Adjective	Verb	Adverb
legal action	Yes	No	No	No
proceeding	Yes	No	No	No

As nouns, proceeding is a hypernym of legal action; that is, proceeding is a word with a broader meaning than legal action:

legal action: a judicial proceeding brought by one party against another; one party prosecutes another for a wrong done or for protection of a right or for prevention of a wrong
proceeding: (law) the institution of a sequence of steps by which legal judgments are invoked

Other hypernyms of legal action include legal proceeding, proceedings.

legal action (noun)	proceeding (noun)
a judicial proceeding brought by one party against another; one party prosecutes another for a wrong done or for protection of a right or for prevention of a wrong	(law) the institution of a sequence of steps by which legal judgments are invoked