social occasion vs social affair

social occasion and social affair both are nouns.

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

As nouns, social occasion and social affair are synonyms defined as:

social occasion and social affair: a formal or official social gathering or ceremony of people

Other synonyms of social occasion include affair, function, occasion, social function, social gathering.

social occasion (noun)	social affair (noun)
a formal or official social gathering or ceremony of people	a formal or official social gathering or ceremony of people