benumb vs numb

benumb is not an adjective while numb is an adjective.

Word	Noun	Adjective	Verb	Adverb
benumb	No	No	Yes	No
numb	No	Yes	Yes	No

As verbs, benumb and numb are synonyms defined as:

Other synonyms of benumb include blunt, dull.

benumb (adjective)	numb (adjective)
	so frightened as to be unable to move; stunned or paralyzed with terror; petrified
	lacking sensation
	(followed by `to') not showing human feeling or sensitivity; unresponsive

benumb (verb)	numb (verb)
make numb or insensitive	make numb or insensitive