ceremony vs affair

ceremony and affair both are nouns.

Word	Noun	Adjective	Verb	Adverb
ceremony	Yes	No	No	No
affair	Yes	No	No	No

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

ceremony (noun)	affair (noun)
the proper or conventional behavior on some solemn occasion	a vaguely specified concern
any activity that is performed in an especially solemn elaborate or formal way	a formal or official social gathering or ceremony of people
a formal event performed on a special occasion	a usually secretive or illicit sexual relationship