sea rover vs sea robber

sea rover and sea robber both are nouns.

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

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

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

Other synonyms of sea rover include buccaneer, pirate.

sea rover (noun)	sea robber (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