looter vs sea rover

looter and sea rover both are nouns.

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

As nouns, sea rover is a hyponym of looter; that is, sea rover is a word with a more specific, narrower meaning than looter:

looter: someone who takes spoils or plunder (as in war)
sea rover: someone who robs at sea or plunders the land from the sea without having a commission from any sovereign nation

Other hyponyms of looter include buccaneer, pirate, sea robber.

looter (noun)	sea rover (noun)
someone who takes spoils or plunder (as in war)	someone who robs at sea or plunders the land from the sea without having a commission from any sovereign nation