lock breaking; lock picking
Refers to the act of forcibly opening or manipulating a lock without a key. Can imply either destructive breaking or skillful picking, depending on context.
警察は錠前破りの手口を詳しく調べた。
The police investigated the method of lock picking in detail.
彼は錠前破りの道具を持っていた。
He had tools for breaking locks.
Compound of 錠前 (lock) and 破り (breaking), from the verb 破る (to break). The exact historical origin is uncertain, but the word straightforwardly describes the action of defeating a lock.