Roadblock/ˈrəʊdblɑːk/ Definition 1 of 2Pro Tip 1/2Law Enforcement Used for official police actions to control traffic or catch criminals. The escaped convict was caught at a roadblock. Pro Tip 2/2Unexpected Delay It can surprise drivers and suggest an unplanned interruption in a journey. On our road trip, we encountered a roadblock due to a sudden protest.