An idiom meaning to be barely saved or to have only a very slim chance remaining.
彼は首の皮一枚で試験に合格した。
He passed the exam by the skin of his teeth.
あのチームは首の皮一枚で予選を突破した。
That team scraped through the qualifiers by a hair.
交渉は首の皮一枚でまとまったが、まだ安心はできない。
The negotiation was concluded by the skin of our teeth, but we still can't relax.