leakage vs outflow

leakage and outflow both are nouns.

Word	Noun	Adjective	Verb	Adverb
leakage	Yes	No	No	No
outflow	Yes	No	No	No

As nouns, leakage and outflow are synonyms defined as:

Other synonyms of leakage include escape, leak.

leakage (noun)	outflow (noun)
the discharge of a fluid from some container	the discharge of a fluid from some container
	a natural flow of ground water
	the process of flowing out