postmortem examination vs post-mortem examination

postmortem examination and post-mortem examination both are nouns.

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

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

postmortem examination and post-mortem examination: 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, postmortem.

postmortem examination (noun)	post-mortem examination (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