or gentleman's agreement
an agreement that, although unenforceable at law, is binding as a matter of personal honor.
an unwritten agreement by a socially prominent clique, private club, etc., to discriminate against or refuse to accept members of certain religious, racial, national, or other groups.
Origin of gentlemen's agreement
An Americanism dating back to 1885–90
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a personal understanding or arrangement based on honour and not legally binding
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012