post-mortem vs necropsy

post-mortem and necropsy both are nouns.

Word	Noun	Adjective	Verb	Adverb
post-mortem	Yes	No	No	No
necropsy	Yes	No	No	No

As nouns, post-mortem and necropsy are synonyms defined as:

post-mortem and necropsy: an examination and dissection of a dead body to determine cause of death or the changes produced by disease

Other synonyms of post-mortem include autopsy, PM, post-mortem examination, postmortem, postmortem examination.

post-mortem (noun)	necropsy (noun)
an examination and dissection of a dead body to determine cause of death or the changes produced by disease	an examination and dissection of a dead body to determine cause of death or the changes produced by disease
discussion of an event after it has occurred