Unanimously, without exception, as in The committee voted against the proposal to a man. This expression, first recorded in 1712, uses man in the sense of “everyone.” It continues to be so used despite its sexist tone. To a woman is very occasionally used for unanimous actions in groups that include only women. Also see as one; with one voice.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.