A safecracker is someone who opens locked safes without having the key or combination. Professional safecrackers might work for locksmith companies, helping people who've forgotten their combinations or lost the keys to their own safes. But the word often refers to thieves who break into safes to steal what's inside.

In old movies and detective stories, safecrackers appear as clever criminals who press their ears against safe doors, slowly turning the dial and listening for tiny clicks as the lock's mechanisms align. Real safecracking requires deep knowledge of how locks work. Some safecrackers drill into the safe's mechanism, while others exploit weaknesses in how the safe was designed or manufactured.

The word can also mean someone exceptionally skilled at solving difficult problems or puzzles. If your friend figures out the twist ending of a mystery novel before anyone else, you might joke that they're a real safecracker when it comes to stories.

Today, many safes use electronic locks instead of mechanical combinations, so modern safecrackers need to understand both old-fashioned lock mechanisms and computer security. Banks and security companies sometimes hire former safecrackers as consultants to test their systems and find vulnerabilities before actual thieves do.