"admiring the slim smoothness of her thighs"
"some artists prefer the smoothness of a board"

"his eloquence attracted a large congregation"
"fluency in spoken and written English is essential"
"his oily smoothness concealed his guilt from the police"

"the water was a glassy smoothness"
"the weather system of the Pacific is determined by the uninterrupted smoothness of the ocean"

"the five-speed manual gearbox is smoothness personified"