adj.
极狭的,窄如发丝的

[ noun ]
a very small distance or space
<noun.quantity>
they escaped by a hair's-breadththey lost the election by a whisker

Hairbreadth \Hair"breadth`\ (-br[e^]dth), Hair's breadth
\Hair's" breadth`\ (h[^a]rz"-).
The diameter or breadth of a hair; a very small distance;
sometimes, definitely, the forty-eighth part of an inch.
[Also spelled {hairsbreadth}.]

Every one could sling stones at an hairbreadth and not
miss. --Judg. xx.
16.