adverb of manner vs adverb

adverb of manner and adverb both are nouns.

Word	Noun	Adjective	Verb	Adverb
adverb of manner	Yes	No	No	No
adverb	Yes	No	No	No

As nouns, adverb is a hypernym of adverb of manner; that is, adverb is a word with a broader meaning than adverb of manner:

adverb of manner: An adverb that describes how the action of a verb is carried out.
adverb: a word that modifies something other than a noun

adverb of manner (noun)	adverb (noun)
An adverb that describes how the action of a verb is carried out.	a word that modifies something other than a noun
	the word class that qualifies verbs or clauses