a police officer who directs the flow of traffic, usually at an intersection.
Origin of traffic cop
An Americanism dating back to 1910–15
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for traffic cop
informal a policeman who supervises road traffic
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