›pieces of broken wood and other waste materials found on the beach or floating on the sea: We wandered along the shore, stepping over the flotsam that had washed up in the night.Rubbish and wasteEnvironmental issues›anything or anyone that is not wanted or not considered to be important or useful: The homeless sleep in doorways and stations - we step over their bodies like so much human flotsam.Rubbish and wasteEnvironmental issues