following vs undermentioned

following is a noun but undermentioned is not a noun.

Word	Noun	Adjective	Verb	Adverb
following	Yes	Yes	No	No
undermentioned	No	Yes	No	No

As adjectives, following and undermentioned are synonyms defined as:

following (noun)	undermentioned (noun)
the act of pursuing in an effort to overtake or capture
a group of followers or enthusiasts

following (adjective)	undermentioned (adjective)
going or proceeding or coming after in the same direction	about to be mentioned or specified
in the desired direction
about to be mentioned or specified
immediately following in time or order