coarseness vs graininess

coarseness and graininess both are nouns.

Word	Noun	Adjective	Verb	Adverb
coarseness	Yes	No	No	No
graininess	Yes	No	No	No

As nouns, coarseness and graininess are synonyms defined as:

coarseness and graininess: the quality of being composed of relatively large particles

Other synonyms of coarseness include granularity.

coarseness (noun)	graininess (noun)
looseness or roughness in texture (as of cloth)	the quality of being composed of relatively large particles
the quality of being composed of relatively large particles
the quality of lacking taste and refinement
language or humor that is down-to-earth