Definition of "picketer"

At the first show at U.C.L.A., picketers ended up joining the ticket line to see what the play was about.

2007 June 9, Sharon Waxman, “What’s in a Slur? A New Play Searches for Answers”, in New York Times‎

While hourly workers ponder the agreement, salaried workers at G.M., many of whom encountered picketers blocking plant entrances when they arrived for work on Monday and Tuesday, said they, too, were thankful the strike did not drag on, because there was no upside for them.

2007 September 27, Nick Bunkley, Mary M. Chapman, “Off the Picket Line at G.M., Relieved but Wary”, in New York Times‎