This is the 882nd most frequent Korean word.
반응이
"반응이" means "reaction" or "response" in English.
Here, '반응이' refers to someone's emotional or physical response to a situation.
그의 반응이 정말 놀랍습니다.
His reaction is truly astonishing.
In this sentence, '반응이' is used to describe a subject's reaction to medical treatment.
약물 치료에 대한 반응이 초기에 좋았습니다.
The response to the pharmaceutical treatment was initially good.
'반응이' in this case denotes how a group (the audience) responded to a performance or event.