immediateness vs mediate

immediateness is a noun but mediate is not a noun.

Word	Noun	Adjective	Verb	Adverb
immediateness	Yes	No	No	No
mediate	No	Yes	Yes	No

immediateness (noun)	mediate (noun)
the quickness of action or occurrence
lack of an intervening or mediating agency

immediateness (adjective)	mediate (adjective)
	acting through or dependent on an intervening agency
	being neither at the beginning nor at the end in a series

immediateness (verb)	mediate (verb)
	act between parties with a view to reconciling differences
	occupy an intermediate or middle position or form a connecting link or stage between two others