saury vs billfish

saury and billfish both are nouns.

Word	Noun	Adjective	Verb	Adverb
saury	Yes	No	No	No
billfish	Yes	No	No	No

As nouns, saury and billfish are synonyms defined as:

saury and billfish: slender long-beaked fish of temperate Atlantic waters

Other synonyms of saury include Scomberesox saurus.

saury (noun)	billfish (noun)
slender long-beaked fish of temperate Atlantic waters	giant warm-water game fish having a prolonged and rounded toothless upper jaw
	elongate European surface-dwelling predacious fishes with long toothed jaws; abundant in coastal waters
	primitive predaceous North American fish covered with hard scales and having long jaws with needlelike teeth
	slender long-beaked fish of temperate Atlantic waters