silkiness vs smoothness

silkiness and smoothness both are nouns.

Word	Noun	Adjective	Verb	Adverb
silkiness	Yes	No	No	No
smoothness	Yes	No	No	No

As nouns, smoothness is a hypernym of silkiness; that is, smoothness is a word with a broader meaning than silkiness:

silkiness (noun)	smoothness (noun)
the smooth feel of silk fabric	a texture without roughness; smooth to the touch
	the quality of having a level and even surface
	the quality of being free from errors or interruptions
	the quality of being bland and gracious or ingratiating in manner
	powerful and effective language