postmortem vs succeeding

postmortem is a noun but succeeding is not a noun.

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

postmortem (noun)	succeeding (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

postmortem (adjective)	succeeding (adjective)
occurring or done after death	coming after or following
after death or after an event	(of elected officers) elected but not yet serving