From Longman Dictionary of Contemporary Englishunmarkedun‧marked /ˌʌnˈmɑːkt◂ $ -ˈmɑːrkt◂/ adjective SHOW/BE A SIGN OF#something that is unmarked has no words or signs on it to show where or what it is an unmarked grave an unmarked police car
Examples from the Corpus
unmarked• And I scarcely think the impact would leave the globe unmarked.• For example, they transport schoolchildren to events in unmarked buses, or pick them up from locations outside West Belfast.• I try an unmarked door and it opens to reveal ... yes, stationery again.• The Skunk Works operated as an independent community within Lockheed, its secret activities conducted behind unmarked doors.• an unmarked grave• About 25 percent of the remaining minefields in Bosnia have been marked, leaving 45 percent still unmarked, Mazzafro said.• an unmarked police carunmarked police car• At 8am a convoy of vans and unmarked police cars swept out heading for the addresses.• By the time the unmarked police car was thumping down the motorway to London, the sun teetered on the horizon. 