sea rover vs despoiler

sea rover and despoiler both are nouns.

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

As nouns, despoiler is a hypernym of sea rover; that is, despoiler is a word with a broader meaning than sea rover:

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

Other hypernyms of sea rover include freebooter, looter, pillager, plunderer, raider, spoiler.

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