shipboard soldier vs devil dog

shipboard soldier and devil dog both are nouns.

Word	Noun	Adjective	Verb	Adverb
shipboard soldier	Yes	No	No	No
devil dog	Yes	No	No	No

As nouns, shipboard soldier and devil dog are synonyms defined as:

shipboard soldier and devil dog: a member of the United States Marine Corps

Other synonyms of shipboard soldier include leatherneck, Marine.

shipboard soldier (noun)	devil dog (noun)
a member of the United States Marine Corps	a member of the United States Marine Corps