Entry
  1. Adverb (fukushi), Adverb taking the 'to' particle

    meaningfully (smiling, grinning, etc.); suggestively; broadly; sneeringly

    Onomatopoeic or mimetic word

    にやりと笑って賛成の意思を示した。
    She grinned her approval.

Also written にやり

Pitch on OJAD