expression, godan verb (-u)
smile cheerfully; crack a smile
Describes a bright, cheerful smile, often in response to something pleasant or amusing. The phrase is a fixed expression combining the adverb にっこり (smilingly) with 笑う (to smile/laugh).
赤ちゃんが私を見てにっこり笑った。
The baby smiled cheerfully at me.
彼は嬉しそうににっこり笑ってうなずいた。
He smiled cheerfully and nodded happily.