antemortem vs postmortem

antemortem is not a noun while postmortem is a noun.

Word	Noun	Adjective	Verb	Adverb
antemortem	No	Yes	No	No
postmortem	Yes	Yes	No	No

antemortem (noun)	postmortem (noun)
	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

antemortem (adjective)	postmortem (adjective)
preceding death	occurring or done after death
	after death or after an event