Grammar
-이/가 아니라서
because it is not
Form
Noun + -이/가 아니라서 — “because it is not…”, “since it is not…”.
Function
Presents the negation of an identification as the cause or explanation for what follows.
Why this form?
N-이/가 아니지만 — “it is not…, but…”: expresses contrast or concession, not a cause.
N-이/가 아니니까 — “since it is not…”: often grounds a decision, conclusion, or instruction.
How to build it
아니다 + -아서/어서 → 아니라서, not *아니어서 in this ordinary construction.
Forms not to confuse
- N-이/가 아니지만
학생은 아니지만 공부해요. — I’m not a student, but I study.
- N-이/가 아니니까
제 일이 아니니까 걱정하지 마세요. — Since it’s not my responsibility, don’t worry.
Examples
네, 저도 혼자가 아니라서 정말 안심돼요. — Yes, I’m really relieved because I’m not alone.
오늘은 휴일이 아니라서 가게가 열었어요. — Since today is not a holiday, the shop is open.