-(으)ㄹ세라
lest, for fear that
Anxiety expressed in a literary register. It is -(으)ㄹ까 봐 lifted into written Korean, and you will meet it in novels far more often than in speech.
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When to use it
Vowel stems take -ㄹ세라, consonant stems -을세라, and a ㄹ stem adds nothing: 만들세라.
The first clause names the feared outcome, and the second describes the care taken to avoid it: 아이가 깰세라 발소리를 죽였다 — she muffled her footsteps for fear of waking the child.
Because the second clause is a precaution, it is usually a careful or gentle action — 조심스럽게, 살며시, 죽이다, 감추다.
The register is distinctly literary. In conversation, -(으)ㄹ까 봐 is the form people actually use.
How to attach it
| Stem type | Form | Example |
|---|---|---|
| Ends in a vowel | -ㄹ세라 | 깨다 → 깰세라 |
| Ends in a consonant | -을세라 | 늦다 → 늦을세라 |
| Ends in ㄹ | nothing added | 만들다 → 만들세라 |
| Second clause | a precaution | 발소리를 죽였다 |
| Never takes tense | plain stem only | 깼을세라 is wrong |
| Spoken version | -(으)ㄹ까 봐 | 깰까 봐 |
In use
아이가 깰세라 발소리를 죽이고 걸었다.
She walked softly, lest the child wake.
행여 늦을세라 서둘러 집을 나섰다.
He hurried out for fear of being late.
눈물을 들킬세라 고개를 돌렸다.
She turned away lest her tears be seen.
행여 다칠세라 아이의 손을 꼭 잡았다.
He held the child’s hand tightly for fear she might be hurt.
모양이 흐트러질세라 조심스럽게 만들었다.
He shaped it carefully, lest it lose its form.
비밀이 새어 나갈세라 목소리를 낮추었다.
They lowered their voices for fear the secret would get out.
Compared with
-(으)ㄹ까 봐
Identical meaning, everyday register. -(으)ㄹ까 봐 is what people say; -(으)ㄹ세라 belongs to narrative prose.
깰까 봐 조용히 했어요. (speech) / 깰세라 발소리를 죽였다. (writing)
-지 않도록
-지 않도록 states the purpose plainly and neutrally; -(으)ㄹ세라 adds the emotion of dread.
깨지 않도록 조용히 했다. (so as not to wake) / 깰세라 (in fear of waking)
행여
The adverb 행여 — “by any chance” — is a frequent companion, reinforcing the anxious tone.
행여 늦을세라 / 행여 다칠세라
Watch out
아이가 깼을세라 발소리를 죽였다.
아이가 깰세라 발소리를 죽였다.
-(으)ㄹ세라 never carries tense. The feared event has not happened.
모양이 흐트러질세라 크게 흔들었다.
모양이 흐트러질세라 조심스럽게 다루었다.
The second clause has to be a precaution. A careless action contradicts the fear stated.
야, 늦을세라 빨리 가자.
야, 늦을까 봐 빨리 가자.
-(으)ㄹ세라 is literary. In speech, -(으)ㄹ까 봐 is the natural form.
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