くるり

〈物もの〉がくるりと回まわるfor something to spin around in one complete turn
彼かれは椅い子すの上うえでくるりと回まわった。
He spun around once on the chair.
くるりと向むきを変かえるto turn around abruptly and change direction
彼かの女じょはくるりと向むきを変かえて去さっていった。
She turned around abruptly and walked away.
〈物もの〉をくるりと包つつむto wrap something up completely in one swift motion
プレゼントをくるりと包つつんだ。
I wrapped the present up in one swift motion.
くるりとした目めbig, beautifully round eyes
彼かの女じょはくるりとした目めが印いん象しょう的てきだ。
Her big, round eyes are striking.

Kanji

くるっと
くるっと and くるり both describe a quick spinning or sudden motion, but くるっと sounds slightly more casual and abrupt while くるり often implies a single, complete, more deliberate turn.
突とつ然ぜんN3sense 2
突然 is a neutral, formal word for something happening suddenly, while くるり is a mimetic adverb that adds a vivid, quick-turn feel to a sudden change.
パッチリ sense 4
ぱっちり emphasizes eyes being wide open and clear, while くるり in this sense emphasizes the round, doll-like shape of the eyes.
くるん
くるり and くるん both describe a single quick spin or turn, but くるり is more common and often used for a person or object turning around abruptly, while くるん emphasizes a soft, rounded motion.

くるくるN1sense 1
くるくる describes repeated, continuous spinning while くるり describes just one complete turn, so learners must not use them interchangeably despite the similar sound.

Onomatopoeic or mimetic word; the exact origin is uncertain.