にこにこ

にこにこ is a 擬態語(ぎたいご) (mimetic word) that describes a warm, gentle, continuous smile showing happiness or friendliness.

Common patterns

• にこにこする: to smile (ongoing state)
• にこにこ顔(がお): a smiling face
• にこにこしながら: while smiling
• にこにこと話(はな)す: to talk with a smile

Similar smile words

• にっこり: a single bright smile (one-time action, often warm)
• にやにや: grinning, smirking (can imply mischief or something suspicious)
• にたにた: smirking unpleasantly (negative nuance)
• ほほえむ: to smile (verb, more literary)

Usage

にこにこ always has a positive, warm nuance. It suggests a genuine, pleasant smile — never sarcastic or forced. Commonly used to describe children, friendly people, and pleasant interactions.