necessitate vs demand

necessitate is not a noun while demand is a noun.

Word	Noun	Adjective	Verb	Adverb
necessitate	No	No	Yes	No
demand	Yes	No	Yes	No

As verbs, necessitate and demand are synonyms defined as:

Other synonyms of necessitate include ask, call for, involve, need, postulate, require, take.

necessitate (noun)	demand (noun)
	the act of demanding
	required activity
	an urgent or peremptory request
	the ability and desire to purchase goods and services
	a condition requiring relief

necessitate (verb)	demand (verb)
require as useful, just, or proper	request urgently and forcefully
cause to be a concomitant	claim as due or just
	summon to court
	ask to be informed of
	lay legal claim to
	require as useful, just, or proper