keratitis vs redness

keratitis and redness both are nouns.

Word	Noun	Adjective	Verb	Adverb
keratitis	Yes	No	No	No
redness	Yes	No	No	No

As nouns, redness is a hypernym of keratitis; that is, redness is a word with a broader meaning than keratitis:

keratitis: inflammation of the cornea causing watery painful eyes and blurred vision
redness: a response of body tissues to injury or irritation; characterized by pain and swelling and redness and heat

Other hypernyms of keratitis include inflammation, rubor.

keratitis (noun)	redness (noun)
inflammation of the cornea causing watery painful eyes and blurred vision	red color or pigment; the chromatic color resembling the hue of blood
	a response of body tissues to injury or irritation; characterized by pain and swelling and redness and heat