'Sea rover' definitions:

Definition of 'sea rover'

(from WordNet)
noun
Someone who robs at sea or plunders the land from the sea without having a commission from any sovereign nation [syn: pirate, buccaneer, sea robber, sea rover]

Definition of 'Sea rover'

From: GCIDE
  • Sea rover \Sea" rov"er\ One that cruises or roves the sea for plunder; a sea robber; a pirate; also, a piratical vessel. [1913 Webster]