빛 좋은 개살구다 · 빛 좋은 개살구 같다
all show and no substance; looks good but disappoints
Example
그 회사는 겉으로는 화려하지만 빛 좋은 개살구예요.
That company looks glamorous on the outside, but it's all show and no substance.
Word parts
개살구 is a wild apricot: bright-colored but sour. 개- often means 'wild, inferior.'