Adverb (fukushi), Adverb taking the 'to' particle, Suru verb
grinning; smirking
Onomatopoeic or mimetic word
なにニヤニヤしてるんだよ。何かいいことあったのか。What are you smirking at? Did something good happen?
Also written にやにや
Adverb (fukushi), Adverb taking the 'to' particle, Suru verb
grinning; smirking
Onomatopoeic or mimetic word
Also written にやにや