-지만
but / although
Meaning
-지만 joins two ideas that contrast: the second part goes against what the first part might lead you to expect. It attaches to verb and adjective stems.
Form
Any verb or adjective stem
stem + 지만
비싸다 → 비싸지만
Past
-았/었지만
가다 → 갔지만
Noun + 이다
이지만
학생 → 학생이지만
Examples
비싸지만 맛있어요.
It's expensive, but delicious.
한국어는 어렵지만 재미있어요.
Korean is hard, but it's fun.
어제는 바빴지만 오늘은 괜찮아요.
I was busy yesterday, but today I'm fine.
Watch out
Contrast, not just "and"
-고 adds another fact: 싸고 맛있어요 (cheap and delicious). Use -지만 when the two parts pull in different directions: 비싸지만 맛있어요. In speech, -는데 can also show contrast, often more softly.