a person who drives a car inexpertly, especially slowly or overcautiously, in the manner of one who drives infrequently.
Origin of Sunday driver
First recorded in 1915–20
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for sunday driver
informal a person who drives slowly, timorously, or unskilfully, as if used to driving only on Sundays when the roads are relatively quiet
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