supper vs social affair

supper and social affair both are nouns.

Word	Noun	Adjective	Verb	Adverb
supper	Yes	No	No	No
social affair	Yes	No	No	No

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

Other hypernyms of supper include affair, function, occasion, social function, social gathering, social occasion.

supper (noun)	social affair (noun)
a light evening meal; served in early evening if dinner is at midday or served late in the evening at bedtime	a formal or official social gathering or ceremony of people
a social gathering where a light evening meal is served