emphasis vs emphasize

emphasis is a noun but emphasize is not a noun.

Word	Noun	Adjective	Verb	Adverb
emphasis	Yes	No	No	No
emphasize	No	No	Yes	No

emphasis (noun)	emphasize (noun)
intensity or forcefulness of expression
the relative prominence of a syllable or musical note (especially with regard to stress or pitch)
special and significant stress by means of position or repetition e.g.
special importance or significance

emphasis (verb)	emphasize (verb)
	to stress, single out as important
	give extra weight to (a communication)