An onomatopoeic adverb describing a crisp, sharp, or neat appearance/attitude; often used as 'kiritto shita'.
面接ではきりっとした服装で行ったほうが印象がいい。
It's better to go to an interview dressed neatly; it makes a good impression.
彼はいつもきりっとした表情で話すので頼もしく見える。
He always speaks with a composed expression, which makes him look dependable.
朝の冷たい水で顔を洗うと、目がきりっと覚める。
Washing your face with cold water in the morning sharpens your eyes and wakes you up.