function vs affair

function and affair both are nouns.

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

As nouns, function and affair are synonyms defined as:

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

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

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

function (noun)	affair (noun)
the actions and activities assigned to or required or expected of a person or group	a vaguely specified concern
what something is used for	a formal or official social gathering or ceremony of people
a set sequence of steps, part of larger computer program	a usually secretive or illicit sexual relationship
a formal or official social gathering or ceremony of people
a formal or official social gathering or ceremony
(mathematics) a mathematical relation such that each element of a given set (the domain of the function) is associated with an element of another set (the range of the function)
a relation such that one thing is dependent on another

function (verb)	affair (verb)
perform duties attached to a particular office or place or function
perform as expected when applied
serve a purpose, role, or function