post-mortem vs discussion

post-mortem and discussion both are nouns.

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

As nouns, discussion is a hypernym of post-mortem; that is, discussion is a word with a broader meaning than post-mortem:

Other hypernyms of post-mortem include give-and-take, word.

post-mortem (noun)	discussion (noun)
an examination and dissection of a dead body to determine cause of death or the changes produced by disease	an exchange of views on some topic
discussion of an event after it has occurred	an extended communication (often interactive) dealing with some particular topic