postmortem examination vs post-mortem

postmortem examination and post-mortem both are nouns.

Word	Noun	Adjective	Verb	Adverb
postmortem examination	Yes	No	No	No
post-mortem	Yes	No	No	No

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

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

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

postmortem examination (noun)	post-mortem (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