nearly; almost; on the verge of
Used when something bad or dramatic almost happened but was narrowly avoided. Often followed by a phrase describing the averted outcome, such as ～ところだった.
It nearly turned into a major accident.
あわや衝突しそうになったが、間一髪で避けた。
We almost collided, but avoided it by a hair's breadth.
It was almost a major accident.
It nearly turned into a collision, but the driver swerved just in time.
He narrowly avoided falling.