whiteness vs pearl

whiteness and pearl both are nouns.

Word	Noun	Adjective	Verb	Adverb
whiteness	Yes	No	No	No
pearl	Yes	No	Yes	No

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

whiteness: the quality or state of the achromatic color of greatest lightness (bearing the least resemblance to black)
pearl: a shade of white the color of bleached bones

Other hyponyms of whiteness include alabaster, bleach, bone, ivory, off-white, chalk, frostiness, hoariness.

whiteness (noun)	pearl (noun)
the quality or state of the achromatic color of greatest lightness (bearing the least resemblance to black)	a shade of white the color of bleached bones
lightness or fairness of complexion	a smooth lustrous round structure inside the shell of a clam or oyster; much valued as a jewel
the state of being unsullied by sin or moral wrong; lacking a knowledge of evil	a shape that is spherical and small

whiteness (verb)	pearl (verb)
	gather pearls, from oysters in the ocean