require vs necessitate

require and necessitate both are verbs.

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

As verbs, require and necessitate are synonyms defined as:

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

require (verb)	necessitate (verb)
make someone do something	require as useful, just, or proper
consider obligatory; request and expect	cause to be a concomitant
have need of
require as useful, just, or proper