sleekness vs smoothness

sleekness and smoothness both are nouns.

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

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

sleekness (noun)	smoothness (noun)
the smooth feel of silk fabric	a texture without roughness; smooth to the touch
the quality of being well-groomed and neatly tailored	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