whitening vs bleach

whitening and bleach both are nouns.

Word	Noun	Adjective	Verb	Adverb
whitening	Yes	No	No	No
bleach	Yes	No	Yes	No

As nouns, bleach is a hyponym of whitening; that is, bleach is a word with a more specific, narrower meaning than whitening:

whitening: changing to a lighter color
bleach: the act of whitening something by bleaching it (exposing it to sunlight or using a chemical bleaching agent)

whitening (noun)	bleach (noun)
changing to a lighter color	the act of whitening something by bleaching it (exposing it to sunlight or using a chemical bleaching agent)
	the whiteness that results from removing the color from something
	an agent that makes things white or colorless

whitening (verb)	bleach (verb)
	make whiter or lighter
	cause to become white or lighter in color