adverb, adverb taking the 'to' particle
with a squeeze in one's chest; heart-throbbing; choked up
Describes a sudden, tight feeling in the chest caused by strong emotion, such as love, sadness, or nostalgia. Often used in the phrase 胸がきゅんとなる.
彼の笑顔を見て胸がきゅんとなった。
My heart squeezed when I saw his smile.
別れの場面で胸がきゅんとして涙が出た。
I got choked up at the parting scene and tears came out.
Mimetic word; the exact origin is uncertain, but it phonetically represents a sudden tightening or squeezing sensation.