POW vs prisoner of war

POW and prisoner of war both are nouns.

Word	Noun	Adjective	Verb	Adverb
POW	Yes	No	No	No
prisoner of war	Yes	No	No	No

As nouns, POW and prisoner of war are synonyms defined as:

POW and prisoner of war: a person who surrenders to (or is taken by) the enemy in time of war

POW (noun)	prisoner of war (noun)
a person who surrenders to (or is taken by) the enemy in time of war	a person who surrenders to (or is taken by) the enemy in time of war