관건이 · 관건을
the key (factor), the crux
Example
이번 선거의 관건은 젊은 층의 투표율입니다.
The key factor in this election is turnout among young voters.
Word parts
관 gate bar+건 key
Literally 'gate bolt and key' — the part that holds everything shut or open.
Good to know
Typical pattern: ~이/가 관건이다 'the key is ~': 시간이 관건이에요.
Related words