sea rover sea·ro·ver uncommon noun 1. someone who robs at sea or plunders the land from the sea without having a commission from any sovereign nation Synonymspiratebuccaneersea robbersea rover Related words Word family buccaneer Broader terms plunderer Narrower terms corsairsea kingLaffiteMorganRobertsTeach WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.