white-out vs whiteout

white-out is not a noun while whiteout is a noun.

Word	Noun	Adjective	Verb	Adverb
white-out	No	No	Yes	No
whiteout	Yes	No	Yes	No

As verbs, white-out and whiteout are synonyms defined as:

white-out and whiteout: lose daylight visibility in heavy fog, snow, or rain

white-out (noun)	whiteout (noun)
	an arctic atmospheric condition with clouds over snow produce a uniform whiteness and objects are difficult to see; occurs when the light reflected off the snow equals the light coming through the clouds

white-out (verb)	whiteout (verb)
lose daylight visibility in heavy fog, snow, or rain	lose daylight visibility in heavy fog, snow, or rain
	cover up with a liquid correction fluid