Someone who brings in their own packed lunch (e.g., in a brown paper bag), as for work or school. The brown baggers of the office always go out to the park to eat on nice days.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
A person who brings his or her own supplies, as in The architects of the new office designed a space for brown baggers to eat lunch. The term originated in the 1930s in Britain for very serious students who carried their books about with them in brown briefcases or bags. That usage crossed the Atlantic within a few decades. However, in America from the 1960s on, it has primarily been used for persons who brought their own liquor in a brown paper bag, either legitimately or surreptitiously, to a public place or restaurant not licensed to sell it, or for those who took their lunch to work.
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.