Negation · 안, -지 않아요

4. Common mistakes

❌ Mistake 1 — 안 before a 하다 noun

✖ 저는 안 공부해요.
✔ 저는 공부 안 해요.
  jeo-neun gong-bu an hae-yo.

공부하다 is a noun plus 하다, so 안 has to sit between them. Putting 안 in front of the whole word breaks the verb in a place where Korean does not allow it. The long form 공부하지 않아요 is always safe.

❌ Mistake 2 — 안 with 이에요

✖ 저는 학생이 안이에요.
✔ 저는 학생이 아니에요.
  jeo-neun hak-saeng-i a-ni-e-yo.

The word 안 does not combine with 이에요. For "is not" with a noun, you need the special word 아니에요. It comes after the subject marker 이 or 가.

❌ Mistake 3 — 안 있어요

✖ 저는 돈이 안 있어요.
✔ 저는 돈이 없어요.
  jeo-neun do-ni eop-seo-yo.

The opposite of 있어요 is 없어요, a separate word. 안 있어요 is not the normal way to say I have none. It points to staying or not staying somewhere, so it gives the wrong meaning here.

❌ Mistake 4 — 안 when you mean "cannot"

✖ 저는 수영을 안 해요.
✔ 저는 수영을 못해요.
  jeo-neun su-yeong-eul mo-tae-yo.

The first sentence is grammatical, but it means I do not swim, by choice. If you want to say I am not able to swim, you must use 못. This mistake sounds rude or strange, because the listener hears a choice.

❌ Mistake 5 — 이 after a vowel

✖ 제 친구는 의사이 아니에요.
✔ 제 친구는 의사가 아니에요.
  je chin-gu-neun ui-sa-ga a-ni-e-yo.

의사 ends in a vowel, so the subject particle must be 가. Use 이 only after a consonant, as in 학생이 아니에요. This is the same rule as 이/가 in every other sentence.