expression
not a single person; no one at all
Used with a negative predicate to emphasize that there is absolutely no one who does or is something. Often translated as 'not a single person' or 'no one at all'.
その会議には一人として賛成する者はいなかった。
Not a single person at the meeting agreed.
彼の意見に一人として反対する人はいなかった。
There was no one at all who opposed his opinion.