What does "hair's breadth" mean?

A very small amount or distance.

What is a synonym for "hair's breadth"?

Common synonyms include: hair, hairbreadths, hairsbreadth, hairsbreadths, whisker.

noun

noun ·Rare ·Advanced level

Noun

1
A very small amount or distance. idiomatic
"hair's-breadth escapes [narrow escapes]"
2
a very small distance or space wordnet

"hair's-breadth escapes [narrow escapes]"