arms vs implements of war

arms and implements of war both are nouns.

Word	Noun	Adjective	Verb	Adverb
arms	Yes	No	No	No
implements of war	Yes	No	No	No

As nouns, arms and implements of war are synonyms defined as:

Other synonyms of arms include munition, weaponry, weapons system.

arms (noun)	implements of war (noun)
weapons considered collectively	weapons considered collectively
the official symbols of a family, state, etc.