war cry vs war whoop

war cry and war whoop both are nouns.

Word	Noun	Adjective	Verb	Adverb
war cry	Yes	No	No	No
war whoop	Yes	No	No	No

As nouns, war cry and war whoop are synonyms defined as:

war cry and war whoop: a yell intended to rally a group of soldiers in battle

Other synonyms of war cry include battle cry, rallying cry.

war cry (noun)	war whoop (noun)
a yell intended to rally a group of soldiers in battle	a yell intended to rally a group of soldiers in battle
a slogan used to rally support for a cause