What it means
Means you only just managed it, with no breathing space at all, like scraping a pass or dodging trouble by a hair. The image is deliberately daft because teeth don’t have skin, so the gap you had was basically imaginary. It’s an old idiom, even shows up in the Bible, and it’s perfect for near misses and last-second saves.
Usage examples
"I hit submit on the online form at 11:59. By the skin of my teeth. The site froze for a second and my heart nearly stopped."
"We caught the last train by the skin of our teeth, doors closing as we jumped on."
"He passed the exam by the skin of his teeth, one mark over the line."
"I got to the airport by the skin of my teeth after the cab took the scenic route from hell."
"She kept her job by the skin of her teeth after that meeting. One more mistake and she'd have been out."
Where it comes from
It comes from the King James Bible, in Job 19:20, where the line reads I am escaped with the skin of my teeth. That odd image is the whole charm of it, because teeth don't have skin, so it means you got away by a vanishingly tiny margin. From there it settled into everyday English as a classic near-miss idiom.
Other ways to say it
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