flatness vs taste sensation

flatness and taste sensation both are nouns.

Word	Noun	Adjective	Verb	Adverb
flatness	Yes	No	No	No
taste sensation	Yes	No	No	No

As nouns, taste sensation is a hypernym of flatness; that is, taste sensation is a word with a broader meaning than flatness:

flatness: a deficiency in flavor
taste sensation: the sensation that results when taste buds in the tongue and throat convey information about the chemical composition of a soluble stimulus

Other hypernyms of flatness include gustatory perception, gustatory sensation, taste, taste perception.

flatness (noun)	taste sensation (noun)
the property of having two dimensions	the sensation that results when taste buds in the tongue and throat convey information about the chemical composition of a soluble stimulus
inactivity; showing an unusual lack of energy
the property of having little or no contrast; lacking highlights or gloss
a deficiency in flavor
a want of animation or brilliance