kidney failure vs nephrosis

kidney failure and nephrosis both are nouns.

Word	Noun	Adjective	Verb	Adverb
kidney failure	Yes	No	No	No
nephrosis	Yes	No	No	No

As nouns, nephrosis is a hypernym of kidney failure; that is, nephrosis is a word with a broader meaning than kidney failure:

kidney failure: inability of the kidneys to excrete wastes and to help maintain the electrolyte balance
nephrosis: a disease affecting the kidneys

Other hypernyms of kidney failure include failure, kidney disease, nephropathy, renal disorder.

kidney failure (noun)	nephrosis (noun)
inability of the kidneys to excrete wastes and to help maintain the electrolyte balance	a disease affecting the kidneys
	a syndrome characterized by edema and large amounts of protein in the urine and usually increased blood cholesterol; usually associated with glomerulonephritis or with a complication of various systemic diseases