坦々たる

(1) 粗さ、隆起、うねまたは不連続性のない表面を持つ(having a surface free from roughness or bumps or ridges or irregularities; "smooth skin"; "a smooth tabletop"; "smooth fabric"; "a smooth road"; "water as smooth as a mirror")(having a surface free from roughness or bumps or ridges or irregularities)

⇒鏡と同じぐらい静かな水面(having a surface free from roughness or bumps or ridges or irregularities)

(2) 特に質、能力、大きさまたは度合において例外的ではない(not exceptional in any way especially in quality or ability or size or degree; "ordinary everyday objects"; "ordinary decency"; "an ordinary day"; "an ordinary wine")(not exceptional in any way especially in quality or ability or size or degree)

⇒普通のワイン(not exceptional in any way especially in quality or ability or size or degree)

(3) 紛争または騒動または戦争に邪魔されない(not disturbed by strife or turmoil or war; "a peaceful nation"; "peaceful times"; "a far from peaceful Christmas"; "peaceful sleep")(not disturbed by strife or turmoil or war)

⇒穏やかな眠り(not disturbed by strife or turmoil or war)

(4) 例えば、形またはテクスチャーのように変化を伴わず水平である、直線であるあるいは規則的であるさま同じ同一平面、または、何か他のものと同じ高さであること（すなわち、同等）(being level or straight or regular and without variation as e.g. in shape or texture; or being in the same plane or at the same height as something else (i.e. even with); "an even application of varnish"; "an even floor"; "the road was not very even"; "the picture is even with the window")(being level or straight or regular and without variation as e.g. in shape or texture)(or being in the same plane or at the same height as something else (i.e. even with))

⇒絵は窓と並行である(or being in the same plane or at the same height as something else (i.e. even with))

(5) 斜面のない表面を持つこと、一部分がもう一つより高くないまたは低くない傾斜(having a surface without slope, tilt in which no part is higher or lower than another; "a flat desk"; "acres of level farmland"; "a plane surface"; "skirts sewn with fine flat seams")(having a surface without slope, tilt in which no part is higher or lower than another)

⇒繊細な平たい縫い目で縫われたスカート(having a surface without slope, tilt in which no part is higher or lower than another)