working party vs social unit

working party and social unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
working party	Yes	No	No	No
social unit	Yes	No	No	No

As nouns, social unit is a hypernym of working party; that is, social unit is a word with a broader meaning than working party:

working party: a group of people working together temporarily until some goal is achieved
social unit: an organization regarded as part of a larger social group

Other hypernyms of working party include unit.

working party (noun)	social unit (noun)
a group of people working together temporarily until some goal is achieved	an organization regarded as part of a larger social group