outlet vs outfall

outlet and outfall both are nouns.

Word	Noun	Adjective	Verb	Adverb
outlet	Yes	No	No	No
outfall	Yes	No	No	No

As nouns, outfall is a hyponym of outlet; that is, outfall is a word with a more specific, narrower meaning than outlet:

outlet (noun)	outfall (noun)
activity that frees or expresses creative energy or emotion	the outlet of a river or drain or other source of water
an opening that permits escape or release
a place of business for retailing goods
receptacle providing a place in a wiring system where current can be taken to run electrical devices