EntryCommonJLPT N2
  1. Adverb (fukushi), Adverb taking the 'to' particle, Suru verb

    with a friendly grin; smilingly

    Onomatopoeic or mimetic word

    彼女はいつも快活でにこにこしている。
    She is always bright and smiling.

Also written にこにこ

Pitch on OJAD