devil dog vs shipboard soldier

devil dog and shipboard soldier both are nouns.

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

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

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

Other synonyms of devil dog include leatherneck, Marine.

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