whitewash vs cover up

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

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

As verbs, cover up is a hypernym of whitewash; that is, cover up is a word with a broader meaning than whitewash:

Other hypernyms of whitewash include cover.

whitewash (noun)	cover up (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

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