initiative vs beginning

initiative and beginning both are nouns.

Word	Noun	Adjective	Verb	Adverb
initiative	Yes	Yes	No	No
beginning	Yes	Yes	No	No

As nouns, beginning is a hypernym of initiative; that is, beginning is a word with a broader meaning than initiative:

Other hypernyms of initiative include commencement, start.

initiative (noun)	beginning (noun)
the first of a series of actions	the act of starting something
readiness to embark on bold new ventures	the first part or section of something
	the event consisting of the start of something
	the place where something begins, where it springs into being
	the time at which something is supposed to begin

initiative (adjective)	beginning (adjective)
serving to set in motion	serving to begin