(으)면 안 되다

Overview

The grammar pattern (으)면 안 되다 is used to express prohibition or impermissibility of an action. It literally translates to "if you do X, it is not okay/does not work." This structure clearly indicates that a certain action is forbidden, not allowed, or should not be performed.

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Usage

This pattern is widely used in various situations where rules, regulations, or strong advice against an action are being conveyed. It can be used to:

• State a rule or law: For example, "여기서 담배를 피우면 안 돼요" (You are not allowed to smoke here).
• Give a warning or advice: For instance, "늦잠을 자면 안 돼요" (You shouldn't oversleep).
• Express a general prohibition: Such as, "거짓말을 하면 안 돼요" (You must not lie). The nuance is quite strong, implying that performing the action would lead to a negative outcome, a violation, or is simply incorrect.

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Conjugation Rules

The pattern (으)면 안 되다 attaches to the verb stem.

1. If the verb stem ends in a vowel or ㄹ (ri-eul) consonant, attach -면 안 되다.
   • 가다 (to go) -> 가면 안 되다
   • 만들다 (to make) -> 만들면 안 되다
2. If the verb stem ends in a consonant (excluding ㄹ), attach -으면 안 되다.
   • 먹다 (to eat) -> 먹으면 안 되다
   • 읽다 (to read) -> 읽으면 안 되다

The 안 되다 part can be conjugated for tense and politeness levels (e.g., 안 돼요, 안 됩니다, 안 됐어요).

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Knowledge Plus

While (으)면 안 되다 expresses a clear prohibition, its opposite, (으)면 되다, expresses permission or that something is acceptable ("if you do X, it's okay/it works"). For a softer prohibition or a recommendation not to do something, one might use -지 마세요 (don't do X) or -는 게 좋다 (it's good not to do X). However, (으)면 안 되다 carries a stronger sense of "not permitted" or "must not." It's often used when there's an explicit rule or a strong societal expectation.