desensitize vs numb

desensitize is not an adjective while numb is an adjective.

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

As verbs, numb is a hyponym of desensitize; that is, numb is a word with a more specific, narrower meaning than desensitize:

Other hyponyms of desensitize include benumb, blunt, dull, bedaze, daze, stun, besot, stupefy, deaf, deafen.

desensitize (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

desensitize (verb)	numb (verb)
make insensitive	make numb or insensitive
cause not to be sensitive