noun
a bit; a trifle; a tiny amount
Rare literary noun for a very small quantity or degree. Often used in negative contexts to mean 'not even a bit'. Modern equivalents include 少し, わずか, or ほんの少し.
彼の言葉には一毫の真実もなかった。
There was not a grain of truth in his words.
一毫の疑いもなく、彼は正しいと思った。
Without a shadow of a doubt, he thought he was right.