ceremonial occasion vs occasion

ceremonial occasion and occasion both are nouns.

Word	Noun	Adjective	Verb	Adverb
ceremonial occasion	Yes	No	No	No
occasion	Yes	No	Yes	No

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

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

ceremonial occasion (noun)	occasion (noun)
a formal event performed on a special occasion	an event that occurs at a critical time
	a formal or official social gathering or ceremony of people
	a rational motive for a belief or action
	an opportunity to do something
	the time of a particular event

ceremonial occasion (verb)	occasion (verb)
	give occasion to