anger (to see red= to be very angry); danger (red alert, a red flag); special importance (The royal visitor was given red carpet treatment. The day we met will always be a red-letter day for me); left-wings in politics (red point of view) - See more at: http://www.engtest.net/forum/detail.php?type_id=03-01&&topic_id=1811#sthash.GrwuiQkI.dpuf