white violet vs violet

white violet and violet both are nouns.

Word	Noun	Adjective	Verb	Adverb
white violet	Yes	No	No	No
violet	Yes	Yes	No	No

As nouns, violet is a hypernym of white violet; that is, violet is a word with a broader meaning than white violet:

white violet: short-stemmed violet of eastern North America having fragrant purple-veined white flowers
violet: any of numerous low-growing violas with small flowers

As nouns, violet is a hypernym of white violet; that is, violet is a word with a broader meaning than white violet:

white violet: tall North American perennial with heart-shaped leaves and white flowers with purple streaks
violet: any of numerous low-growing violas with small flowers

white violet (noun)	violet (noun)
short-stemmed violet of eastern North America having fragrant purple-veined white flowers	a variable color that lies beyond blue in the spectrum
tall North American perennial with heart-shaped leaves and white flowers with purple streaks	any of numerous low-growing violas with small flowers

white violet (adjective)	violet (adjective)
	of a color intermediate between red and blue