verb (used with or without object), flubbed, flub·bing.
to perform poorly; blunder; bungle: He flubbed the last shot and lost the match.
Origin of flub
An Americanism dating back to 1920–25; origin uncertain
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
an embarrassing mistake or blunder
verb flubs, flubbing or flubbed
(intr) to blunder or make an embarrassing mistake
Word Origin for flub
C20: of origin unknown
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
1924, American English, perhaps suggested by fluff, flop, etc. Related: Flubbed; flubbing. As a noun, by 1952.
Online Etymology Dictionary, © 2010 Douglas Harper