adverb
turning around; spinning around; curling up
Describes a quick, single rotation or a curling motion. Often used with verbs like 回る, 巻く, or 丸まる.
See also: くるり
猫がくるっと丸まって寝ている。
The cat is sleeping curled up in a ball.
彼はくるっと振り返って笑った。
He turned around quickly and smiled.
adverb, noun or participle which takes 'suru'
round and charming (eyes)
Describes eyes that are round and cute, often with a する verb. Compare with くるり, which lacks the charming nuance.
彼女のくるっとした大きな目が印象的だ。
Her big, round, charming eyes are striking.