-(으)면 안 되다
Quick answer: -(으)면 안 되다 means must not — the rule says no.
How to form it
No final consonant → -면 안 되다 · final consonant → -으면 안 되다
In Korean: 받침 X → -면 안 되다 받침 O → -으면 안 되다
What to know
This is the flat opposite of -아/어도 되다 from 11-1. Notice that Korean builds it out of -(으)면 — «if you do it, it is not allowed». The 안 belongs to 되다, not to the verb, so it never moves: 찍으면 안 돼요, never 안 찍으면 돼요, which would mean something else entirely.
Examples
- 사진을 찍으면 안 돼요.You must not take photos.
- 여기에서 담배를 피우면 안 돼요.You must not smoke here.
- 교실에서 떠들면 안 돼요.You must not make noise in the classroom.
Where it's taught
HanDa Level 2 (TOPIK I), Lesson 22: 사진을 찍으면 안 돼요 — You must not take photos. Also in the Level 2 book.
Practise -(으)면 안 되다 out loud
In the HanDa app this is Level 2, Lesson 22 — drills, a speaking check and an AI teacher that corrects what you say. Free for 7 days.