sea robber vs sea rover

sea robber and sea rover both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea robber	Yes	No	No	No
sea rover	Yes	No	No	No

As nouns, sea robber and sea rover are synonyms defined as:

sea robber and sea rover: someone who robs at sea or plunders the land from the sea without having a commission from any sovereign nation

Other synonyms of sea robber include buccaneer, pirate.

sea robber (noun)	sea rover (noun)
someone who robs at sea or plunders the land from the sea without having a commission from any sovereign nation	someone who robs at sea or plunders the land from the sea without having a commission from any sovereign nation