also: にたぁー
adverb taking the 'to' particle
with a grin; with a devilish smile
Mimetic adverb describing a sly, self-satisfied, or mischievous grin, often used with 笑う or する. Related to にたり.
See also: にたり
彼はいたずらを成功させて、ニタァと笑った。
He grinned devilishly after pulling off his prank.
悪戯っぽい顔でニタァとする。
He gives a sly grin with a mischievous look.