This is the 19349th most frequent Korean word.
알은체했다
Pretended to know or recognize.
In this sentence, "알은체했다" is used to describe someone acknowledging or giving a sign of understanding toward something, despite initial appearance of disinterest.
그는 모르는 척했지만 내 농담에 알은체했다.
He pretended not to know, but responded to my joke.
Here, "알은체했다" conveys the notion of recognizing or showing an acknowledgment upon hearing the name.
아이들은 선생님의 이름을 들었을 때 바로 알은체했다.
The children immediately recognized when they heard the teacher's name.
In this usage, "알은체했다" indicates a silent or intuitive acknowledgment or recognition without explicit communication.