the art or practice of achieving, demonstrating, or assuming superiority in one's rivalry with a friend or opponent by obtaining privilege, status, status symbols, etc.: the one-upmanship of getting into the president's car pool.
Also one-ups·man·ship [wuhn-uhps-muh n-ship] /ˈwʌnˈʌps mənˌʃɪp/.
Origin of one-upmanship
Also called upmanship, upsmanship.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
informal the art or practice of achieving or maintaining an advantage over others, often by slightly unscrupulous means
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
1952, from noun phrase one up "scoring one more point than one's opponent" (1919).
Online Etymology Dictionary, © 2010 Douglas Harper