declassification vs decrease

declassification and decrease both are nouns.

Word	Noun	Adjective	Verb	Adverb
declassification	Yes	No	No	No
decrease	Yes	No	Yes	No

As nouns, decrease is a hypernym of declassification; that is, decrease is a word with a broader meaning than declassification:

declassification: reduction or removal by the government of restrictions on a classified document or weapon
decrease: the act of decreasing or reducing something

Other hypernyms of declassification include diminution, reduction, step-down.

declassification (noun)	decrease (noun)
reduction or removal by the government of restrictions on a classified document or weapon	the act of decreasing or reducing something
	the amount by which something decreases
	a change downward
	a process of becoming smaller or shorter

declassification (verb)	decrease (verb)
	decrease in size, extent, or range
	make become smaller