Word familyverbreddenadjectivereddishreddyred-bloodedredbrickred-facedredhandedred-hotrednounreddishnessrednessred alertredbackredbellyredbreastredbudredcapred cardredcoatRed CrescentRed Crossredcurrantredfishred flagred giantredheadredlegred meatredneckredpollredrootredshankredshirtredskinredstartredstreakred taperedtopred-topredwaterredwingredwoodadverbredly
ˌred ˈflag noun [countableC]
American EnglishAmE something that shows or warns you that something might be wrong, illegal etc 示警红旗
Examples from the Corpus
red flag• Volcanologists now recognize these oscillations as a red flag that a volcano is entering a dangerous phase.• It was a red flag, a symbol of an anti-education attitude.• All we needed was a red flag to warn the locals that we might be about to frighten the horses.