inferior vs mediocre

inferior is a noun but mediocre is not a noun.

Word	Noun	Adjective	Verb	Adverb
inferior	Yes	Yes	No	No
mediocre	No	Yes	No	No

inferior (noun)	mediocre (noun)
a character or symbol set or printed or written beneath or slightly below and to the side of another character
one of lesser rank or station or quality

inferior (adjective)	mediocre (adjective)
written or printed below and to one side of another character	poor to middling in quality
of or characteristic of low rank or importance	moderate to inferior in quality
of low or inferior quality	lacking exceptional quality or ability
having an orbit between the sun and the Earth's orbit
lower than a given reference point
falling short of some prescribed norm