fundraiser vs social occasion

fundraiser and social occasion both are nouns.

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

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

fundraiser: a social function that is held for the purpose of raising money
social occasion: a formal or official social gathering or ceremony of people

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

fundraiser (noun)	social occasion (noun)
a social function that is held for the purpose of raising money	a formal or official social gathering or ceremony of people
someone who solicits financial contributions