brainstorming vs group action

brainstorming and group action both are nouns.

Word	Noun	Adjective	Verb	Adverb
brainstorming	Yes	No	No	No
group action	Yes	No	No	No

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

brainstorming: a group problem-solving technique in which members spontaneously share ideas and solutions
group action: action taken by a group of people

brainstorming (noun)	group action (noun)
a group problem-solving technique in which members spontaneously share ideas and solutions	action taken by a group of people