disclosure vs news leak

disclosure and news leak both are nouns.

Word	Noun	Adjective	Verb	Adverb
disclosure	Yes	No	No	No
news leak	Yes	No	No	No

As nouns, news leak is a hyponym of disclosure; that is, news leak is a word with a more specific, narrower meaning than disclosure:

disclosure: the speech act of making something evident
news leak: unauthorized (especially deliberate) disclosure of confidential information

disclosure (noun)	news leak (noun)
the speech act of making something evident	unauthorized (especially deliberate) disclosure of confidential information