affair vs matter

affair and matter both are nouns.

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

As nouns, affair and matter are synonyms defined as:

Other synonyms of affair include thing.

affair (noun)	matter (noun)
a vaguely specified concern	that which has mass and occupies space
a formal or official social gathering or ceremony of people	(used with negation) having consequence
a usually secretive or illicit sexual relationship	some situation or event that is thought about
	a vaguely specified concern
	a problem
	written works (especially in books or magazines)

affair (verb)	matter (verb)
	have weight; have import, carry weight