This is the 14423rd most frequent Korean word.
무자비해지고
"Becoming ruthless" or "growing merciless."
Here, '무자비해지고' (becomes ruthless) is used to describe a change in behavior when experiencing anger.
그 사람은 화가 나면 무자비해지고 논리적이지 못하다.
That person becomes ruthless and illogical when angry.
In this sentence, '무자비해지고' refers to having to adopt a ruthless demeanor in response to harsh circumstances.
전쟁 상황에서 군인들은 무자비해지고 결단력을 보여야 한다.
In war situations, soldiers must become ruthless and show decisiveness.
The term '무자비해지고' here is applied to survival instincts, emphasizing its use in a survival context.