Must Not (-(으)면 안 되다)
-(으)면 안 되다
Expresses prohibition, meaning 'must not' or 'is not allowed to'.
Pattern
Verb stem + -(으)면 안 되다
Explanation
-(으)면 안 되다 literally means 'if you do X, it won't do' and is used to express prohibition or things that are not allowed. Use -면 안 되다 after vowel-ending stems and -으면 안 되다 after consonant-ending stems. 여기서 담배를 피우면 안 돼요 means 'You must not smoke here'.
This pattern is the negative counterpart of -아/어도 되다 (permission). While -아/어도 되다 says 'you may', -(으)면 안 되다 says 'you must not'. It is commonly used for rules, regulations, and strong advice against doing something.
In conversation, this pattern is used to warn people or express that something is not acceptable. 늦으면 안 돼요 (You must not be late). It is softer than a direct command but still carries clear authority. Teachers, parents, and signs frequently use this pattern.
Examples
여기서 사진을 찍으면 안 돼요.
Yeogiseo sajineul jjigeumyeon an dwaeyo.
You must not take photos here.
수업 중에 전화하면 안 돼요.
Sueop junge jeonhwahamyeon an dwaeyo.
You must not make phone calls during class.
늦으면 안 돼요.
Neujeumyeon an dwaeyo.
You must not be late.
거짓말하면 안 돼요.
Geojinmalhamyeon an dwaeyo.
You must not lie.
Common Mistakes
Wrong
찍으면 안되요.
Correct
찍으면 안 돼요.
되다 conjugates to 돼요 (not 되요), and 안 is written as a separate word before 돼요.
Wrong
사진을 찍면 안 돼요.
Correct
사진을 찍으면 안 돼요.
After consonant-ending stems (찍), use -으면, not -면.
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