cover up vs whitewash

cover up is not a noun while whitewash is a noun.

Word	Noun	Adjective	Verb	Adverb
cover up	No	No	Yes	No
whitewash	Yes	No	Yes	No

As verbs, whitewash is a hyponym of cover up; that is, whitewash is a word with a more specific, narrower meaning than cover up:

Other hyponyms of cover up include gloss over, hush up, sleek over.

cover up (noun)	whitewash (noun)
	a specious or deceptive clearing that attempts to gloss over failings and defects
	wash consisting of lime and size in water; used for whitening walls and other surfaces
	a defeat in which the losing person or team fails to score

cover up (verb)	whitewash (verb)
hide from view or knowledge	exonerate by means of a perfunctory investigation or through biased presentation of data
	cover with whitewash
	cover up a misdemeanor, fault, or error