실마리가 · 실마리를
a clue, a lead; the end of a thread
Example
형사는 작은 단서에서 사건의 실마리를 찾았어요.
The detective found a lead in the case from a small clue.
Word parts
Built on 실 'thread' — the loose end you pull to untangle a knot.
Good to know
Collocations: 실마리를 찾다/잡다 'to find a lead', 실마리가 풀리다 'to start getting solved'.