초록동색이 · 초록동색을
birds of a feather, like sticks with like
Example
초록동색이라고 그 둘은 금방 친해졌어요.
Birds of a feather — the two of them became friends right away.
Word parts
초 grass+록 green+동 same+색 color
Literally 'grass and green are the same color.'
Good to know
Often quoted as the saying 초록은 동색.