This is the 19006th most frequent Korean word.
아니구나
"아니구나" means "Oh, it's not" or "I see it's not."
Here, '아니구나' serves as a realization or conclusion within a thought, expressing that something is determined not to be the case.
그게 사실이 아니구나.
That is not true.
In this sentence, '아니구나' is used to express a deduction or understanding that the person is concluded not to be a doctor.
그 사람이 의사 아니구나.
That person is not a doctor.
Similarly, here '아니구나' indicates a realization or understanding that the place is concluded not to be the station.