late 14c., "smoothness, evenness," from smooth (adj.) + -ness.
admiring the slim smoothness of her thighs
some artists prefer the smoothness of a board
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