滑らか・滑か|なめらかnameraka[2]nakadaka (mid-high)

1. na-adjectivesmooth (of a surface); glassy; velvety; soft
   海うみは穏おだやかに、そしてなめらかに見みえる。↗

   The sea looks calm and smooth.
2. na-adjectivesmooth (of an action, proceedings, etc.); fluent (speech); fluid; trouble-free
3. na-adjective, mathcontinuously differentiable

• Synonym円滑えんかつNeutralCovers things going smoothly and without a hitch (「円滑な運営」), typically for the running of affairs; 「滑らか」 also covers smooth surfaces.
• SynonymスムーズNeutralA loanword for smooth, problem-free progress (「スムーズに進む」), very common in speech; 「滑らか」 also covers surface texture.
• SynonymすべすべCasualColloquial. Describes skin or stone that feels smooth to the touch (「すべすべの肌」); tactile only, while 「滑らか」 also covers fluent actions and speech.
• Synonym平滑へいかつWrittenWritten/formal prose. A noun for flat, even smoothness (「平滑な表面」), found mostly in technical descriptions.
• RelatedしなやかNeutralDescribes supple, graceful movement (「しなやかな動き」), with the emphasis on elasticity; 「滑らか」 stresses smoothness itself.
• Related潤滑じゅんかつNeutralA noun for lubrication (「潤滑油」), used mostly of machines or figuratively; 「滑らか」 describes the smooth feel or flow itself.
• Relatedきめ細かきめこまかNeutralMeans fine in texture or meticulous and attentive (「きめ細かな対応」), often for service; 「滑らか」 is about smoothness, not fineness.
• RelatedなだらかNeutralRefers to gentle slopes and gradual change (「なだらかな坂」); 「滑らか」 stresses a smooth surface or smooth progress.
• Antonym粗いあらいNeutralThe antonym: coarse or rough (「目が粗い」「粗い肌」), the direct opposite of 「滑らか」.
• AntonymザラザラNeutralThe antonym for touch: gritty and rough to the feel (「ザラザラした手触り」), opposite of 「滑らか」.

Use 「滑らか」 for smooth surfaces and for fluent speech or smooth progress (「滑らかな肌」「滑らかな口調」). For a purely tactile feel say 「すべすべ」; for smooth-running business say 「円滑」 or 「スムーズ」. The opposites are 「粗い」 and 「ザラザラ」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. つるつるしているさま。よく滑すべるさま。
2. 澱おどみのないさま。滞とどこおりなく進すすむさま。