casualty vs injured party

casualty and injured party both are nouns.

Word	Noun	Adjective	Verb	Adverb
casualty	Yes	No	No	No
injured party	Yes	No	No	No

As nouns, casualty and injured party are synonyms defined as:

casualty (noun)	injured party (noun)
a decrease of military personnel or equipment	someone injured or killed in an accident
an accident that causes someone to die
someone injured or killed in an accident
someone injured or killed or captured or missing in a military engagement