risk group vs social group

risk group and social group both are nouns.

Word	Noun	Adjective	Verb	Adverb
risk group	Yes	No	No	No
social group	Yes	No	No	No

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

risk group: a group of people that share the likelihood of being affected by a given event (developing a disease, chance of being cured, etc.).
social group: people sharing some social relation

risk group (noun)	social group (noun)
a group of people that share the likelihood of being affected by a given event (developing a disease, chance of being cured, etc.).	people sharing some social relation