cover-up vs hiding

cover-up and hiding both are nouns.

Word	Noun	Adjective	Verb	Adverb
cover-up	Yes	No	No	No
hiding	Yes	No	No	No

As nouns, hiding is a hypernym of cover-up; that is, hiding is a word with a broader meaning than cover-up:

cover-up: concealment that attempts to prevent something scandalous from becoming public
hiding: the activity of keeping something secret

Other hypernyms of cover-up include concealing, concealment.

cover-up (noun)	hiding (noun)
concealment that attempts to prevent something scandalous from becoming public	the activity of keeping something secret
	the state of being hidden