사자성어 are four-syllable idioms from Classical Chinese, common in speeches, news and among educated speakers.
| idiom | literally | meaning |
|---|---|---|
| 일석이조 (一石二鳥) | one stone, two birds | killing two birds with one stone |
| 작심삼일 (作心三日) | resolution for three days | resolutions that don't last |
| 이심전심 (以心傳心) | from heart to heart | unspoken understanding |
| 우왕좌왕 (右往左往) | going right, going left | running around in confusion |
| 동문서답 (東問西答) | east question, west answer | an irrelevant answer |
| 대기만성 (大器晩成) | great vessels are finished late | late bloomer |
| 자업자득 (自業自得) | reap what you sow | you brought it on yourself |
| 금시초문 (今時初聞) | first hearing now | news to me |
| 십중팔구 (十中八九) | eight or nine out of ten | most likely |
| 유비무환 (有備無患) | prepared, no worries | better safe than sorry |