Webster's 1828 Dictionary
SMOOTHNESS
n. 1. Evenness of suface; freedom from roughness or asperity; as the smoothness of a floor or wall; smoothness of the skin; smoothness of the water.
2. Softness or mildness to the palate; as the smoothness of wine.
3. Softness and sweetness of numbers; easy flow of words. Virgil, though smooth where smoothness is required, is far from affecting it.
4. Mildness or gentleness of speech; blandness of address.
Webster's 1913 Dictionary
SMOOTHNESS
SMOOTHNESS Smooth "ness, n.
Defn: Quality or state of being smooth.
New American Oxford Dictionary
smoothness
smooth ness |ˈsmo͞oT͟Hnis | ▶noun the quality or state of being smooth: the smoothness of her skin | the evacuation went off with remarkable smoothness.
Oxford Dictionary
smoothness
smooth |ness |ˈsmuːðnəs | ▶noun [ mass noun ] the quality or state of being smooth: the smoothness of her skin | the evacuation went off with remarkable smoothness.
Oxford Thesaurus
smoothness
smoothness noun 1 the smoothness of the road surfaces: evenness, levelness, flatness, plainness. ANTONYMS unevenness, roughness. 2 his dress shirt gleamed white against the tanned smoothness of his freshly shaved skin: clean-shavenness, smooth-shavenness, hairlessness. ANTONYMS roughness, hirsuteness. 3 the strength of glass is usually down to its surface smoothness: glossiness, gloss, shine, shininess, gleam, glassiness, sheen, lustre, brightness, sleekness, silkiness, polish, burnish. ANTONYMS dullness. 4 this fat substitute has the smoothness associated with fat: creaminess, even consistency. ANTONYMS lumpiness. 5 the smoothness of the sea: calmness, stillness, tranquillity, placidness, serenity, evenness, flatness, glassiness. ANTONYMS roughness, choppiness. 6 the engine has a V12 -style smoothness: steadiness, smooth running, regularity, rhythm, rhythmicity, freedom from interruption, flow, frictionlessness, fluidity, fluency. ANTONYMS irregularity, jerkiness. 7 this system was cumbersome but worked with reasonable smoothness: straightforwardness, ease, easiness, effortlessness, simplicity. ANTONYMS trouble. 8 the strength of champagne is belied by its smoothness of flavour: mellowness, mildness, pleasantness, blandness, softness. 9 the smoothness of the sounds: softness, mellowness, sweetness, sweet sound, sweet tone, prettiness, silveriness, mellifluousness, melodiousness, musicality, lilt, lyricism, harmony, euphony. ANTONYMS raucousness. 10 she was irritated by his smoothness: suaveness, urbaneness, urbanity, sophistication, polish, finish, courteousness, grace, smooth talking, glibness, persuasiveness, slickness, oiliness, ingratiation, unctuousness; informal smarminess. ANTONYMS gaucheness.
Sanseido Wisdom Dictionary
smoothness
sm ó oth ness 名詞 U 1 なめらかさ ; 平坦 (たん ); 平穏 .2 順調さ ; 円滑さ .3 人当たりのよさ ; (味 音の )なめらかさ ; 口先上手 .4 平静, 穏やかさ .